User:Spineflu

Fan cards are unofficial Dominion kingdom cards created by fans of the game for personal use.

Fan Card Creation Guide

The Fan Card Creation Guide is an extensive collection of tips and guidelines for fan created cards written by user rinkworks; Aquila later wrote an expansion/updated companion piece to it. The guide is well respected and often referenced in the design and critique of fan made cards.

The rinkworks guide is reproduced here in its entirety, with edits for clarity, formatting, and omitting outdated (first edition) information, with additional content from Aquila and spineflu

Introduction

Way, Way TLDR: Playtest your fan cards.

The first rule about creating custom fan cards for Dominion is that you can ignore every single rule about it if you want to. Dominion is a game. Its purpose is fun. If you've got a card idea that sounds fun, do it. Playtest it. If it remains fun after scrutiny, keep playing with it.

Donald X. Vaccarino, the creator of Dominion, on house rules and variants: "I encourage people to play whatever game variants they want, provided they comply with local laws and are agreed upon by all players."

However, this guide might help you create balanced cards without falling into as many pitfalls along the way. If you get past all those, you might still have trouble figuring out how to cost your cards. This guide might help you there, too. Additionally, the later sections of the guide discuss issues related to creating artwork for your cards, printing them, and using them.

Dominion is a very simple, highly flexible game model, and it's very easy to add to. With that flexibility, though, is the potential to make uninteresting ideas. Whilst they may not be flawed, your ideas could get to be disappointing in some way after playing with them for a while. Particularly disappointing if you went through the trouble of getting them printed out. This guide aims to help make your good ideas into great ones before the final send-off to print, big reveal to your friends, etc.; it goes through the design process, identifying where people can take a bad turn, aiming to help refine your card ideas to be just what you want them to be. Whether a single card or a whole bunch of them, or your own expansion, this is going to help.

This guide may look like a rather serious, studious look into the field of Dominion design, but I'm well aware this isn't the most important thing in life and I'm not pretending to be a second Donald X. I just settled into playing and learning the game, the idea of making custom cards came up some day, and I fell in love with the thought instantly. I like designing, and Dominion is a simple yet diverse game that is amazingly expandable. This guide is the product of about 2½ years casually exploring the field, written through personal interest and seeing how the forum is continually active.

One last note: If you're going into fan card creation with the goal of showing Donald X your cards so he can tell you how good they are and that they'll be in the next dominion expansion, don't. With the exception of Courtyard, DXV dislikes card submissions, avoids the Variants & Fan Cards subforum, and gets upset when they're posted in the endless interview thread. Don't be a jerk to the only person who can get Dominion cards printed legally.

Glossary

Flavour and theme are used interchangeably to refer to a card's name and its story, and how the other properties of the card connect to it. Mechanics and functions/functionality refers to everything the card can do. A card's properties are its name, abilities, types and cost. Direct payload refers to anything that can directly help getting ahead on , so $, +Buys, tokens, gaining Victory cards and sometimes cursing Attacks. Drawing cards, gaining non-Victory cards, other Attacks, and kinda trashing would be indirect payload.

General Tips

Be open minded. When you get an immediate good feeling for an idea, note it down straight away.

Know the rules and makeup of Dominion well (but you don't have to be a top pro player). Refer to the Research section for help.

You will want to break away from your projects occasionally. Don't try to battle through if you're on a time constraint - the end results will not be of the best quality - rather factor them in to your schedule. Keep clear notes so you know what you're doing when you come back.
To make a design fun to play long term, focus on the mechanics first, then its theme. The more open it is to interactions, whilst having a definite primary function so it can't do everything, the more replayable it will be and hence interesting long term.
Design briefs for individual cards should specify something relating to one or more of its properties or needed mechanics, and be understandable to another person.
Each card you make should be on the same power level as the official ones and a fun or interesting play experience.
Before doing any playtesting, imagine your ideas in the game as you create them. See how one change or addition affects every other aspect of it. Running a few solo tests may help.
You should be able to sum up what your ideas do in one quick sentence.
For testing simplicity, get another player to explain what your ideas do.
Upvotes on the dominion strategy forum show a good first impression, not necessarily a good overall design.

Know Your Canon

Be intimately familiar with all of the official Dominion cards and how to make the best use of them. You don't have to be an expert Dominion player, but you should be an expert at knowing what each card does and when and why you'd want to use it. Okay, so you don't technically have to know ALL the cards, but my point is that there are more design principles behind the published cards than you might think at first glance.

For example, do you know why Sea Hag discards the top card of your deck instead of just having you plunk the Curse on top? (Answer: So multiple Sea Hags don't completely destroy your next turn.) Do you know why Tournament gives +1 Action? (Answer: So a player with a Tournament in hand but no Province doesn't have to agonize over the uninteresting decision to risk playing Tournament at the expense of another terminal Action in his hand.) Do you know why Outpost won't let you take more than two turns in a row? (Answer: Otherwise you could build a deck that plays an Outpost every turn, shutting out all other players.)

Knowing why the official cards are the way they are will keep you out of the same traps they avoid.

Beyond the Canon

The Secret Histories and Endless Interview both have extremely valuable insights into what has and hasn't worked with official DXV playtesting.

The Variants and Fan Cards subforum - especially the Weekly Design Contest thread - can be a treasure trove of useful jumping off points and ideas that both work and don't work; a caveat with these is the date they were posted compared to which sets were available as "official" reference at the time - several things that used to be a semi-viable card were suddenly made overpowered in games with Capitalism, or an official card did them better.

Keep It Simple

Simplicity is a good thing. You don't want your cards to be any more complicated than they have to be. If you have an idea for a card, try to boil it down as simply as possible without losing the essence of the idea. Note, by the way, that by "simplicity," I'm talking about the concepts you use, not necessarily how complex and careful the the card text has to be to convey those concepts. Native Village for example, has a wall of text on it, but that's okay since the concept itself is a simple one. Once players learn what it does, they don't have to reread the card text every time just to make sure each use conforms to every nuance.

Swing is a Miss

Try to recognize cards that will be "swingy" and avoid them, unless adding swinginess to the game is your intention. By "swingy," I mean a card that will tip the balance of the game too much, especially in a random way. In general, you want to reward good strategy, not random luck.

As an example, suppose you had an attack card that allowed you to take the top card of the deck of the player to your left. You might get lucky and turn up a Colony, resulting in a 20-point swing in your favor — more than the margin of victory for many if not most Dominion games. Or you might get very unlucky and turn up a Curse, resulting in a 2-point swing against you. With such a card, strategic play scarcely matters. The winner is whoever gets luckier with that attack.

Swinginess does exist in the official Dominion cards but on a dramatically smaller scale. Saboteur turning a Colony into a Province is only a 4-point swing. Swindler turning a Province into a Peddler is a defensible edge case. Thief and Bandit only work on treasure: a plentiful, non-scoring resource. Also note that many of those swingy cards have been removed as of the Second Edition.

Scale Model

Make sure your card scales well to multiple players. It's okay if a card plays differently with different numbers of players — many of the official cards do, like Jester and Pirate Ship —but you don't want a card that only works with a certain number and is brokenly weak or brokenly strong otherwise. Note that it is no accident that Witch affects all opponents, while Tribute only affects one. The other way around, and neither Witch nor Tribute would scale properly with different numbers of players.

Avoid Scripted Play

Try to avoid cards that encourage uninteresting strategies. You probably don't want to disincentivize creative or otherwise interesting play. As a trivial example, let's say you had a Duration card that prohibited other players from playing action cards while it's in play. This would cause all your opponents' Action cards to be dead cards. How would they defend against this? By not buying action cards and pursuing a money strategy instead. That, in turn, would discourage you from using your new Duration card in the first place, and the game would degenerate into a simple race for money.

You can't anticipate everything, but if you spend a little time to think about the impact your custom cards will have, you can save yourself a lot of playtesting time.

Fair isn't Balanced

Just because a card is "fair" doesn't make it "balanced." A card is "fair" if all players have equal opportunity to obtain the card and reap the same benefits from playing it. Fairness is good. But just because a card is fair doesn't make it balanced.

Imagine a Treasure/Victory card that costs , is worth , and counts 100 at the end of the game. It's fair, as all players have equal opportunities to obtain it. But the optimal strategy, dramatically excluding all others, is to buy only those until the pile is gone. And then it doesn't matter what you do, because the loser of that race can't hope to make up the VP deficit with mere Provinces. The card is, while fair, grotesquely unbalanced.

Balance problems with fan cards are unfortunately going to be more subtle than this. Usually it's going to be a judgment call. If Minion, Saboteur, Wharf, and Goons had been fan cards, I'm pretty sure the reaction from experienced Dominion players would be to decry them as unbalanced. They do walk the edge. But the point is that balance isn't an objective yes or no but a judgment call: if they greatly shape the games they're in (as is also the case with Gardens, Witch, Ambassador, and others), does that influence make the game more or less fun?

At the other extreme, as Donald X. has said, if you have a card that doesn't change the game at all, what's the point?

The Design Cycle

Situation

Good news: unlike with the later stages of the design process, your situation can't be criticised. You're making your cards for somebody, for some reason; you want to make sure that person or group of people likes them and the reason is met. Focusing on this gives direction for later. Are you in a games group who want to expand their Dominion their own way? Do you just love creativity and want to make ideas that work? Will you want to share your ideas with the general public so they could play them? After determining who your audience is, what do they like most about Dominion, their favourite cards and play styles?

Note down your target audience and their likes before anything else, as honestly as you can. You now know right away what kind of ideas will bring the most fun. No point thinking about the meanest Attack card if your games group is mostly softies; unless you're aiming to open their minds. And generally speaking, the wider your audience is or the less you know about them, the more simplicity is favoured, so more people can understand your cards; unless your preferred audience is those who like complexity. Similarly a strategy focus is better for Joe Bloggs, as that's how the official Dominion cards are set; unless your audience is those who want to water the serious strategy side of Dominion down.

Next, note down your primary motive for making cards. It may seem daft, but this will help you stick to the main excitement you have for Dominion and avoid deviating away from it too far when you make new ideas. It may also identify trends in how you will design, and pitfalls you could fall into.

Some Motives and their tendencies

You want to focus on a specific flavour

The story and flavour of a game are important to its enjoyability, giving it some sense. If you're making an expansion, it will probably have a central flavour, and there could be card names connected to it that just have to be there. And who is saying that you need to stick to European history? For the general public you might stick to it as they expect it, but otherwise, nobody. The flavour can also help some to remember what a card does. Sometimes you can springboard onto a brilliant mechanic idea by thinking about the flavour first, and when you do, get that idea down on paper quickly. It's by no means wrong to think down this route, especially if your audience is casual players, but bear in mind: ultimately, what will make a card fun to play long term is what it does, not its flavour. If you play frequently, you'll notice the novelty of flavour fades away if a card plays bad. Let's say you resonate with the thought of medieval Scouts and like the official card because of this; it is, though, a weak card and drab play experience. You would, at least in time, inevitably choose to use Patrol over Scout, and you'd probably love Patrol if it were named Scout.

So: the ideal is having both great flavour and mechanics, but it's better to focus on mechanics first if you want to use your cards for a good long time.

Another risk to prioritising flavour is the mechanics may end up being very specific to it, narrow in functionality and not very fun in too many different games. The rest of the examples here are different mechanics motives.

Expanding on a Mechanic, Expanding on an Expansion

There's a good amount of design space in many of mechanics and expansions. Playing with the expansion a lot you may see how something missing could fit in. You will probably come to a final result you're confident in and will like playing with; however, it may not turn out as different or as exciting a play experience as you hope long term. The design process has already been heavily worked for the set, so you could wind up going over the same thought processes as Donald. Consider the whole expansion carefully, and read its Secret History. You could find that ideas you have can already be achieved by certain interactions in it, or there are good reasons your idea doesn't exist. So really check that your ideas are suitably different and interesting. In the research section there's some tips on using each official mechanic effectively.

Uncovered mechanic, maybe one seen in another game

To make a card you'll enjoy for a long time that adds a lot to the game, this can be a very effective start. It's why each new Dominion expansion covers a new mechanic; it makes a more interesting thus successful product. Your mechanic might be applied to one single card, or several; perhaps it becomes the centre of your own expansion. It might need new components; be open to this to give yourself more design room, but keep in mind your audience may not like handling and storing too many extra bits. It is possible, though, that a new mechanic could detract from the compelling gameplay of Dominion. Consider the core concepts of the game; deck building, card interactions, strategy, understanding and adapting to game flow, some skill. Will your idea add to or take away from these?

You get a vibe when you mentally combine different card properties together

You'll very likely hit upon something exciting. Get that combination written down pronto in case you forget it. You might find out exactly why you feel it would be effective; if you do, try to write that specific reason down, in case the combination of properties doesn't quite let you achieve your idea and you can open out to using different ones to make it happen. From here, simplicity and sensible theme will be your challenge.

“If only there were a card that did this in that game!”

You will easily get a feel of how the card plays before testing it, and you might get a similar vibe that needs writing down quickly. Here especially you'll need to check the idea isn't flawed (see Research section), as in another kingdom the card will be very different. Also it'll be very easy to make a card be too niche to be interesting for a lot of different games; the more open a card is to interactions whilst having a definite function, the more replayable it will be and hence interesting long term. You might put together one super fun kingdom that you can replay and it still be interesting, and that of course is great; but eventually your play group will tire of it and want a change of kingdom. How many different kingdoms can your idea be interesting in, how many different ways are there of using it? Try and elegantly add more functionality if your idea is too narrow.

For the love of creativity

You have the enthusiasm, and the freedom to explore the whole field of Dominion design. You can come across brilliant ideas; but it's easy to get carried away and also make ineffective ones. This guide is written with you in mind, you'd do well to read it and understand good design principles to follow.

Practical Advise

Finally, think of the practicalities; the time you'll put into your design project and the schedule you'll follow, the money and resources needed to print out physical copies if that's your desire, or how and when to post ideas online. These can prepare you for the process ahead and affect how you design.

Regarding time, here's a reality to know in advance: you're going to want occasional breaks from your projects if they're big. Your mind will want to stop the learning processes of studying the depths of the game to check your designs are safe, and you'll get creativity blocks. It's natural; don't try to battle through those times, as your ideas will be poor, rather factor them in to your schedule.

Design Brief - the Purpose of your design Projects

Knowing your audience and why you want to make cards gives you some things to prioritise, a purpose to fulfill. You started off saying you want to make cards; now you can qualify what sort of cards. This qualification becomes your design brief, the bare essentials that your design(s) must be if it's to be considered successful. Try not to add lots to the brief, just the basic essentials; you get to add every desirable trait later in its Specification. Avoid generic terms though; you might want to say 'make exciting cards', but what do you mean by exciting? Or 'different', but how exactly? Or 'that my friend or play group likes', but what's involved there? When you come back from a break, you need to be able to get right back in and keep clear focus. Friends sharing in your project need to understand clearly too.

If you're designing an expansion, it will have an overall brief that most of your cards need to fit. It should include playstyle themes (e.g. Seaside's playstyle themes are the top of the deck and affecting future turns), so that the cards in it have definite interactions with one another. Try to make these themes connected somehow (Seaside's are connected by planning ahead).

If you're making just a batch of cards that aren't necessarily to play together, they probably still have an overall brief of your preferences.

From here, individual cards will each have their own brief. If you have exciting ideas you noted down quickly, these can be made into such briefs. They should each specify something relating to one or more card properties, which may just include abstract concepts of what the card's abilities are to be; so if you later need to tweak the idea, you have its core concept that must stay as is, making things simpler.

With an expansion, you may put a few individual briefs you have high hopes in together, and they might start it off. Alternatively or in addition, you can wait until you mentally develop each chosen theme as described in the Design Ideas section, so it'll be easier to make fitting ones.

Once you have your briefs, they should ideally be set for good. They're a solid basis on which you can build a sound final outcome. Some briefs might be asking the impossible though, two or more things that cannot all be met or something that cannot make for a fair, balanced or interesting card. You might come to identifying this later in the design process, in which case you will have to adjust the brief. The more knowledge you have of the makeup of Dominion, be it by play experience or by research, the more likely you are to avoid a flawed brief. So, that's the logical next step.

Research

Research may sound boring, but in this case it's nice to do: simply play [dominion.games Dominion]! Of course, it'll take lots of games and several expansions for yourself to know enough to make failsafe, quality cards. You can and probably will read up what others have learned by their playing it, like here on this forum or on Discord. The collective opinion of others gets a better general consensus. Sure you might sit down and read everything at once, but probably you'll look up whatever's necessary for each of your card ideas, each brief, as you make them. You might even find inspiration for new ideas too.

With that said, the rest of this section is some generally useful stuff pooled together into one place for convenience (more concrete, specific examples are below in the Common Pitfalls section):

What makes an official Dominion card interesting?

It isn't always good! Analysing whether or not it's relevant to the best strategies of a game should be interesting every time. If you're using a card in every game and winning, things will get boring.
It's simple to understand, at least in time. Players aren't thinking about what it'll actually do every time they play it so they're free to think strategy.
Each one is suitably different from what other cards do. Try to make sure your ideas will be different from any official ones.
Each is as good as it can be, with no room for improvement. Well, it's more true with newer cards as Donald's got better designing them. Lesson being, time and experience will improve your ideas, but also look for ways to improve as you playtest them. More on this later.
They're mostly balanced.
They don't make luck too big a factor in winning. It's unavoidable, but they don't emphasise it. People buy Dominion as a strategy game, but you might be making less strategic, more chance-based cards for a change to this. Make random effects gentle.

People's different fun factors

Interactivity between players; there is always a little to be had in every game, such as with emptying piles to push the game towards its end.
Cards that have several possible functions (each related somehow so they aren't doing everything), enabling creative play.
Cards needing good play skill to use well feel more rewarding.
Adding a mild randomness makes for a more casually enjoyable game.
3-pile endings add an interactive spin, especially in 2-player games.

People's bad points about Dominion, and possible avenues of course correction

Not enough player interaction. This can be remedied via cards like Tournament, or cards that use Artifacts
Shuffle and draw luck can decide some games without strategy being too involved. This can be nudged via cards that sift (like Dungeon or Warehouse) or shuffle-fixers (like Star Chart or Scavenger).
Cards that take a long time to resolve, either by following the instructions or by causing numerous deep decisions, make players take long turns so they can make the opponents feel disengaged. This can be resolved by using fewer complex cards, or fewer cards that require a decision to be made.
Long games get boring or too taxing on the brain to be enjoyable. Again, this can be course-corrected by not using Colony/Platinum kingdoms and limiting use of junking cards (like Cultist, Familiar, or Masquerade.
Setup time; you can't do much about this as a fan card designer unless you want to program your own homebrew dominion client.
4+ player games tend to cause too much pressure on 3-pile endings to be enjoyable, which limits possible strategies. You can't do much about this either, other than not play 4+ player games.

High skill vs Low skill

You might want to make challenging cards hard to use well even for experienced players, or easy ones for a more relaxing game. How do you make them? Compare the Empires expansion with the base set or Renaissance, as Donald designed these to be high skill and low skill respectively. High skill cards look for fine margins: precise times to play/buy/gain, or how often to do so; precise play order of cards during the turn; decks built in exact ways, with each of these rewarding well. Low skill cards make these margins wide, easy to attain or discern, or ignore them. High skill cards avoid being random as much as possible, whilst low skill cards don't mind or may like some randomness added.

What makes a card strong?

Every game is different, and every card can be amazing one game, terrible the next. That's how things should be. But for general strength, likelihood of being good in a game, play experience with the card is the real indicator. The Dominion Cards Lists on the General Discussion forum give the average consensus of serious players for the official cards, to give an idea for what's strong. Not many people vote and affect the rankings there, so it isn't reliable evidence, but still good.

The ThunderDominion rankings from Discord give consensus of cards' strength within sets rather than cost brackets.

Using Existing Mechanics Effectively

Types

If you focus on a certain type combo for designs, you could get a narrow, inflexible space to work in, which can limit potential. You might do so to achieve certain necessary interactions amongst your card ideas, particularly within an expansion, but otherwise just add the relevant types to fit the abilities. Use a new type only when you need to mention it in a card's instructions, like with Knights referring to themselves and Gathering with Defiled Shrine, or if it indicates something extra to do at setup like Looter.

Action

The vast majority of cards are Actions; it's the main phase of Dominion, and they have the biggest influence as to what the best strategies are in each game. They need a resource, namely 'Actions', in order to be played, so unless they give +1 Action or Villagers their effects on play will be stronger than a Treasure or Night at the same cost. Since they're played first, they can have a large impact on how the rest of the turn goes.

Treasure

They always give direct payload. Make drawing cards with them very hard if you have them draw at all. Keep in mind Actions have already been played, yet the Action resource carries over to the Buy phase. You can't normally play Treasures after you've bought something. Though you may be used to playing all your Treasures down at once, they are technically played one at a time.

Victory

With the possible exceptions of Overgrown Estate and alt-VP like Gardens in an empty deck, these always give VP. Donald gives some good insight into alt VP cards (those that can make alternate strategies to Provinces, like Gardens or Fairgrounds) here. Between these and VP tokens, VP cards can be stacked up so points multiply per copy you have, but clog up the deck with weak or useless cards. If you make a playable Victory card that helps the deck, the effect should be weak for the card's cost; always think of it as a source of VP, and think what would be interesting to gain as a way to get ahead a little. Covering a narrow but useful effect works well as the VP gives a constant reason to buy.

Attacks

see: Attack Pitfalls

Reactions

see: Reaction Pitfalls

Curses

Only use this type if your idea replaces the original Curses. If you attach it to kingdom cards and give them negative VP to try and offset something powerful, you can trash them later so there's no disadvantage, so it'll almost always be right to get them. You might give each other player some VP tokens instead though, to simulate a permanent mark against your score.

Durations

The card stays in play for however many turns as long as it's tracking something, be that effects for your following turns and/or during each other player's turns. Remember, start of turn effects are effectively the same as playing a normal Action with +1 Card +1 Action then the effect, so just +1 Card like Caravan is actually the same as playing Laboratory; typically the later effects are stronger than the immediate, and the immediate needs to be weak to balance it. The total amount given across the turns is a lot for the card's cost, but in balance staying out of deck for some turns means multiple copies are needed to keep an effect constantly in play, and they can miss shuffles by staying in play at Clean-up. This type is a diverse and useful way to implement a lot of different mechanics, so be open to using it, just as all the newest expansions from Adventures on have done. Between Durations and Projects: Durations can be multiplied with copies in the deck (with repeated buys) or Thrones, or effects that can't be multiplied call for a bit more work to put out; Projects work right away without deck cycle delay and are continuous.

Shelters

Don't give them too much immediate power; the early game is very influential, so they could end up dictating the way to play every game they're used in. Be very careful around extra money, as the significant boost in strength from $4-cost to $5-cost cards is partly down to the odds of getting a hand of 5 Coppers in the opening over 4 and Estate. They can add weak but often useful effects to decks, could get better late game, have interesting interactions between them, but should still be reasonable to trash.

Ruins / Looters

Ruins should be weak and $0 cost like the official ones are, so there's as little effect from randomness as possible, just enough to be interesting. You should ask, though, if making more Ruins would actually be worth the cost, because how much could they add to the game for all those cards and your money? The official ones do everything they need to do (unless you don't have Dark Ages, of course). Looters can be strong with Ruins for self benefit, or give them out with Attacks when Curses would be too harsh or when you specifically want $0 cost cards, weak Actions, the Ruins type or several different cards in the opponents’ decks.

Command

Command is new type that has several rules innately attached to it. If a Command plays a Duration, it stays out for as long as it does. Cards played are left in their location (which could be anywhere there are cards), so any effect that needs them to move, like Reserve cards and those that trash themselves to produce an effect, won't work (every self trash needs to say 'if you do' trash it). Commands from the Supply are good for when diversity and flexibility are important to your idea's interest, the ability to become whatever kingdom card is available when you need it, or to first be an available trasher then something else when trashing is done. Commands from places where you don't know the cards that are there make for randomness, or player interactivity if targeting an opponent's hand or deck; bear in mind that this interactivity may not be pleasant as a player's work goes to help someone else.

Reserve & Tavern Mat

The Tavern mat is simply a space for cards to be set aside on; the effect this has is different for each card. If the card removes itself from the Tavern mat at some time, it has the Reserve type (although Distant Lands doesn't follow this), and if it's moved into play, it is 'called'. Their being set aside from the deck can be used to balance a powerful on-play effect, if you add some form of payment to get them back (see Wine Merchant). You can be very flexible with what triggers a call, and you could cover very narrow events that would be unrealistic on a Reaction; they don't need to be in hand at the time. Copies of them can be stored up so a call effect could happen multiple times at once. You may think of a toggle effect where being on the mat turns an effect on and removing it turns it off, but think about how easy it will be to remember with the card not being in play; Duration might be an easier format here. Non-Reserve cards can put other non-Reserve cards on the Tavern mat, to both remove them from the deck and be used by the card itself somehow; keep Miser in mind here.

Heirlooms

One card in the deck from the start interacts with multiple from a kingdom pile; there seem to be very diverse options here. Nothing's saying every Heirloom needs to be a Treasure. It's awkward there being 7 Heirlooms replacing the 7 Coppers already. Either you'll make a kingdom card share an official Heirloom or you'll make a rule for when 8 or more Heirlooms show up in a game. Don't give an Heirloom too much immediate power; the early game is very influential, so they could end up dictating the way to play every game you use them in. They can add weak but often useful effects to decks, and the single copy means something that couldn't be done on a kingdom card could be viable. They could get better later on, and they should have a definite interaction with its kingdom pile that doesn't give too much. Think about the Heirloom's average payout over a Copper, and how this will affect the game; will it speed it up or slow it down? When designing the kingdom pile, keep in mind all the mechanics and uses of the Heirloom; it's hard to say which to design first, probably whichever sparked your idea, the cool starting deck mechanic or the kingdom pile needing a singular accompaniment to work.

Night

The Action and Buy phases have passed so you can't give +Cards, +Actions, +Buys or +16px without adding something to make them always useful. The Night type is primarily good for when cards in play, cards not played, cards gained or other events during the turn are important. Unless the events of the whole Buy phase are distinctly involved in their mechanics, pure Nights shouldn't really be direct payload cards, since they'd probably be better as Treasures. They could be gained to the hand, as buying them lets them be used straight away, and Duration effects are easy to put on too, widening the somewhat narrow design space.

Potion

a blank Treasure for $4 needs highly convincing reasons to buy, such as repeated plays producing great effect or accessing a really expensive card. The latter reason can let you make non-Victory cards normally worth $8 or more viable by making Potions part of its cost. Potions are part of the Supply whenever a Potion cost card is in the kingdom.

Non-Supply piles

These are generally paired with one or more Supply piles (consider the Prize pile and Tournament; Madman and Hermit; or Spoils and Marauder/Bandit Camp/Pillage). These can be used to upgrade or give a temporary boost to a player's deck, or can contain powerful cards that are difficult to get. These avoid all Supply pile altering effects (like the +bonus tokens from Adventures) so abilities are fixed and unchangeable, which opens up new possibilities; You can achieve different play ‘modes’ of a kingdom card by exchanging it with the non-Supply card; Different cards could gain the same non-Supply card; you can have two cards heavily depend on each other.

Travellers

Over non-supply pile upgrades, Travellers are probably defined as a card that can upgrade more than once, one stage per turn. Use these to implement a super powerful effect, a whole deck strategy, on the last stage of the line, so it's balanced and interesting by the time taken to get it. You'd think of it first, then the rest of the line. It'll need to be reliable and affected very little by shuffle randomness once played, to ensure the work and wait pay off. The upgrades up to it should complement it, or work against it if it's that powerful. Consider how they affect deck cycling speed too, as that will affect the speed of upgrading. They should escalate in power, can use the advantage of being non-Supply piles, and give varied but related effects so in the right kind of deck you could collect several of different stages. Don't make them do everything though, there are 9 other kingdom piles in the game which need interacting with.

Split Piles

Split piles add more different kingdom cards to games, create competitiveness by players getting the most copies of each card, and make the lower cards be affected by the timing of their availability. The fewer copies of each card in the pile can be useful too, if there's an effect where too many copies is imbalanced. The cards on top need to empty easily so the lower will appear, i.e easy to gain into decks or self-depleting; or returning them to the pile can also be effective to balance a powerful lower card. The lower cards should synergise with the top ones whilst not making a complete strategy.

Landscape cards ("Card-like objects")

For effects outside the deck that affect the player's turn, deck or the whole game. Beware accidentally making an avenue to a golden deck when designing these, since they are generally not an inherently limited resource like a kingdom card is.

Events

These can be bought any number of times unless otherwise specified. Use them to add extra global mechanics to games, or goals to reach, without detracting from kingdom card functions so as to retain the deckbuilding aspect of the game. 'When you gain this' effects on kingdom cards are a similar feature; they are limited to the number of copies in the Supply (unless there are trash gainers) and relate to the other mechanics on the card. These might influence your designs.

Landmarks

Passive effects that to-date have all involved , to affect how the game can be won. They can really add to Dominion's replayability, and really transform the best avenue to take on an otherwise straightforward kingdom. Avoid implying a much longer game with them though.

States

These are really useful. If you have a mechanic idea that you can't implement cleanly another way, here's a blank card you can write things on to make it work. 1 copy of it (per player if needs be) should be all an effect needs, though you can use both sides (see Miserable/Twice Miserable). Particularly good for unique Attacks (the -1 Card and -$1 tokens are essentially States), although you can change the state of all kinds of things.

Boons & Hexes

These add some chance element to a game, good for a more casual audience. They can be set aside from their pile so that a card has some random but fixed abilities for a game, to favour more strategic audiences (although in doing this with Hexes, you will want to consider that card's terminality very, very carefully, since Locusts and Delusion are extremely powerful). In any case, a card using them should also have a constant effect so it has a definite purpose. You could probably make your own Boons and Hexes too, keeping the average power level of the official ones in mind - after all, there were outtakes of each. The random factor is just enough to be interesting; if they were too much stronger, wins could come entirely down to chance too often, not nice for a predominantly strategy game.

Projects

Not hard to comprehend, you buy them once to activate a continuous effect that changes your gameplay (Inheritance is essentially a Project). The main strategic concept is when to buy them (and if asap how quickly the game can let you get there), so cost is important to get right, though you might make 'if' you get them a thing.

Artifacts

Artifacts are Projects that only one player has at a time (Lost in the Woods is essentially an Artifact), creating player interactivity. They can either be easy to take for competitiveness or hard to take for a way to get ahead.

Mats

Mats either track cards set aside for an indefinite amount of time, or hold gained tokens and define what they do.

Tokens

Embargo tokens

These have a defined use on supply piles, but not when given to players; You can make other cards/card-shaped things distribute them. These are an underutilized pile-denial method - other methods make work better, however.

Coin tokens

These are generic. Use them on a card or mat that will define what they do.

Coffers

an accumulation of + $1s to call during any future Buy phase. +1 Coffers is a bit more valuable than + $1 for the extra flexibility, and it's not limited to being useful only at the Action and Buy phase but can be gained at any time. It's bad to make them too easy to collect and hoard as that detracts from the function of the deck.

Villagers

An accumulation of +1 Actions on demand. Villages make for consistent Actions per turn when the deck is lean and can play right through each turn. Villagers make things much more reliable by evading shuffle randomness; this will be temporary unless you keep a constant supply. They make playing Action combos in the right order easier. They can be gained at any time unlike +Actions; use this and their being stored up to make different ways to getting Actions than playing Villages, and if used to make an Action non-terminal make the storing count for something or justify it as a card you could open with.

VP tokens

These make alternative ways to win the game, and they don't harm the deck with weak or useless Victory cards. You need to avoid neverending games where players can keep playing turns just getting VP and nothing else. Every way to gain VP tokens must bring the game closer to an end, which means gaining cards to empty piles; gain them directly, trash them or your own cards so you need to regain things to trash, or you can give direct payload to imply gaining things. Avoid pairing with getting debt as this will have the opposite effect. Another alternative is make the VP gain a one-shot effect (you could use debt then).

Vanilla Adventure tokens

That is, the +1 Card/Action/Buy/$1 tokens - the Buy token is far cheaper to put down than the other 3 overall, but their strength depends a lot on the cards in the game and the player's freedom of choice where the tokens go. Having to spend $6 or $8 whilst adding no card to the deck, or getting Teacher, should reveal to you the power you're handling.

-1 Penalty tokens

That is, the -1 Card and - tokens, these are essentially States, and can only be taken once, meaning attacks that use them don't stack the penalty. Work equally well as self-setback tools for ones' self as attacks on ones' opponents.

The difference between the - token and 1 are that the - token isn't stackable, it can be paid off in the Action phase with +, and you can still buy cards if you have your - token and no money.

- token

Strong when you can take a card below $5 cost with it. Wildly strong if you let it go on Victory piles.

Trashing token

All you can really do is apply it with a different method than paying $3 and a buy.

Estate/Inheritance token

Hard to reuse, you can't really add further abilities to cards that do something, and Estates are at a good price and you start with some.

Journey token

A way to have a card switch between two modes each play. The number of copies you have and/or timing become factors for playing the card well. Always force flipping the token, otherwise it's a “choose one” card.

Debt

Debt is great for making expensive cards, you can't really make a non-Victory card cost more than $8 but in debt it's sensible as you split the cost across several turns; but because of this 8 debt feels equivalent to about $6-7. Don't make such an expensive card be really good early game because it's accessible then: you might involve this easy accessibility in a card's mechanics though, to make an on-buy effect available whenever useful or make getting copies from a kingdom pile more competitive. You can also use debt cost to avoid being affected by abilities referring to $ costs. And remember you can't buy anything if you have debt, it needs paying off immediately.

Using existing Mechanics effectively

Drawing

Having more cards in hand lets you do more, while letting you cycle through the deck; the latter means the card itself can be played more often (unless you trigger a re-shuffle). These reasons make drawing one of the more powerful mechanics; +cards are better than any of the other +vanilla bonuses. Making a draw card non-terminal lets drawn Actions be playable, so it's a lot more powerful (compare Smithy and Lab). Similarly, the presence of a Village in the kingdom makes a terminal draw card much more relevant.

Draw-to-X cards in hand

Plus Cards let you expand your hand to however big, but draw to X liking smaller hands makes for an interesting way to make a deck or a way to counter handsize attacks. For cost, take how many cards you draw from a standard hand of 5 at the start of the turn as a guide; draw to 7 cards is 3 extra in hand, and Library and Scholar have extra effects on them to boost their cost to $5.

Sifting

non-terminal cycling through the deck so you can choose from lots of cards, but usability is limited by hand size not improving; it would be a very strong card if hand size did improve (compare Warehouse at to Forum at ). Generally good for moving junk cards along as an alternative to trashing or getting the order you play your cards in right.

Village

The ability to play more terminal Actions in a turn is crucial to a great many winning decks, so they will be picked up in the majority of games. Very rarely is a Village too bad in a game to not pick up, only if there's another Village better in the game. An interesting Village design isn't about when and when not to use it, but what kind of Action-heavy deck it makes.

Throne

Thrones can turn Actions with +1 Action into villages. Beyond this they're powerful for when you need the versatility between sometimes being drawing and sometimes payload. Throne Room effectively becomes a copy of the card you play next (unless it loses track of it), but King's Court adds more power than what 2 played cards could, which is why it's so strong. Procession can also add deck power. Royal Carriage gets around the problem of finding a target, but it doesn't work with self-moving cards like Madman. Scepter is non-terminal, but playing Actions at the buy phase limits them in various ways. Conclave is an interesting middleground to a traditional Throne design and a Village.

Non-terminals: Actions with +1 Action, Treasures, & Nights

These are quick to resolve, since you can play many of them during a turn. Pay extra attention to how the card synergizes with itself, too.

Cantrips: Actions with +1 Card, +1 Action

The warnings for non-terminals apply more so here. Cantrips effectively replace themselves in your hand, so they're almost not a part of your deck unless there are effects looking for it as a card.

Virtual coin: Non-treasure effects with +16px

Some decks like having these cards in them, like Tactician and draw to X, but generally it's easy to add +$ onto cards whenever direct payload fits the rest of the card's abilities or when +Cards doesn't fit. Combining draw with +$ is very strong, as illustrated by how hard Mercenary and Trusty Steed are to get. Making a variable +$ effect creates a whole potential deck strategy.

+ Buy

This appears quite rarely amongst official cards, reason being that they would let you do too much and 3 piles would empty too often in the average game if more frequent.

Gainers

Workshop variants are great for building, being like +1 Buy + $X (gain a card costing (up to) $X), but unless you're looking to add lots of cards to the deck they lose usefulness later on. Gaining $5s is more potent than gaining $4s and Duchies are made accessible. Gaining a $4 to hand is fairly strong and would probably make a $4.5 cost card by itself.

Trash for Benefit

These seem to feel generally more fun on average. They add extra functionality to the other cards in the kingdom by involving their cost.

Trashers

The ability to trash your starting Estates and Coppers, as well as other junk, is very powerful, the earlier it can be done the better.

Specification

The specification stage is the criteria your project(s) must meet. After research, you should know the points you need to bear in mind for each brief that you have. Now you can make the specification for each of these briefs, starting with the one for the overall expansion if you're doing one of those. This is a list of the criteria your idea must meet; your brief broken down into individual points, what your research identified with regards avoiding bad or flawed design, your audience's preferences, and expansion themes. Include every other desirable point you can think of, even if not essential, in case they can influence any tweaking later or make one variant of an idea favourite over another. When all the more important criteria are met in your spec, your idea is good to go; you can declare your project complete.

There are 3 points that should be in every specification. Of course, no one is forcing you to add these, but they are fundamentally what makes a great fan card.

Must be balanced, be on the same level of power as the official cards. You would do well to make this the most important criterion. Playtesting is important to proving this. Expansions: there should also be balance amongst the cards in it, i.e. no card should be left completely ignored if the expansion is played by itself, and no one card should completely overpower the others.
Must give players a positive experience. Several different factors are involved here, qualify this further according to your target audience's likes, being precise and avoiding generic terms; if it's the general public, go with the official game's fun factors though don't necessarily expect to excite everybody. Expansions: choose mechanical themes that create fun for your audience and make sure the cards in it cover them well. They should feel compelled to play the expansion by itself.
Must play suitably differently from any official card your audience has. (If that's the general public, all of them.) Why make it otherwise?

In notes, the spec can be drawn up into a table, with columns being criteria (it's a good idea to put them in order of importance, so less important ones could get away with being unfulfilled if needs be), reason for criteria, how to test and test results. This will prepare you for playtesting, and identify some things you can test out by yourself to make the experience better for friends if they want to playtest too. (More in the Playtesting section.)

Writing down the reason for each criterion can help confirm how suitable and important it is, in case you should see the need to re-evaluate later; this may happen if you identify you have 2 or more points that can't possibly all be met, and you need to work out which to ditch. It will also help you to see how well justified you are in taking designs down certain directions, which can be either a confidence boost or a guide in a better direction, both needed. You'll fill in the how to test column later, once the spec becomes a design idea.

Here are some suggestions for further criteria:

Be easy to learn, simple to understand. A complex or wordy card should quickly make sense. (Reason: each game with it is otherwise less relaxing or enjoyable and more of an academic exercise.) *Expansions: interactions between the cards can be as easy or as hard to spot as you like, but the less rules errata you need to make for them the better.
Be usable in any kingdom. (Reason: because your audience fully randomises each game, and that's how official cards are designed.) Expansions: to be truly defined as an expansion, you should have this in the spec of all the cards in it. You may be making a set of cards to play by themselves though, in which case this point is optional and you call the set a Dominion spin-off.
Have short enough ability text to allow for a large enough font size to read easily. (Reason: an easier play experience overall, and some audiences need it.)
Be safe from any possible future card design that doesn't exist officially yet. (Reason: they could exist as fan cards that your audience potentially plays with.)
For expansions, you could specify the number of cards there are to be in the set, the number at each price point, how many should use a certain mechanic, or definite card flavours that have to be there to reflect the expansion theme.

Design Ideas

Design ideas are how to translate your specs into effective designs.

At last, time to unleash your creative flair! You've set your restrictions, you've got an idea of where your cards are going, now you can set them off on their design journey. You could still take bad turns despite all of that work beforehand, so go carefully.

Start with the card properties you mentioned in your brief. Then stop. Imagine the card like this in your mind; get the nature of the card, asking these questions:

What's it like in the deck, in your hand, played, bought?
How would other players feel?
What are all the things it does in every situation?
Do those things feel pleasant and elegant all together or is there a clash?
Does it feel too similar to an official card?
What will it combo with? Any broken interactions with anything?
Compared to official cards, does it need more power or less power? Or what cost seems best?
Is it fulfilling all of the important points in the spec?

After the first imagining, see if you can add another property; think what will fit well and be interesting. After adding another property, stop again and go over the same imagination process, identifying the differences. Keep doing this until you have all the necessary properties. This imagining is one of the big keys to being a good designer. With time, you'll be able to do it quicker and develop an innate sense for fan card design, creating good ideas from scratch. That said, newer designers can come across fantastic designs first time, so don't think there must by default be an improvement to make if you imagine everything's good!

You may come across several things that could work from the base idea. In such case, write down the different variants and test out which is best.

Translating concepts into Dominion mechanics can be a challenge. Writing the instructions clearly and succinctly is another. Here you'll want to look up official cards that do similar things and learn their wording. If you have a new mechanic, you may have to use a verb not covered by official wording and (hypothetically) explain it in your card's rulebook.

But at what point do you stop adding things? How much functionality do you add? You should be able to sum up everything your card does in one quick sentence (without mentioning any of the unconditional +bonuses when you play it). You can do this with each of the official cards; Noble Brigand and Pirate Ship look wordy, but they're simply 'steal their money if they're rich, give them a little if they're poor' (notice how the Robin Hood flavour helps here) and 'steal their money to become better payload' respectively. This proves them as easy to learn and remember, and it gives them a pleasing elegance. That's probably two big points in your spec covered.

As you keep thinking about your idea, as the direction it's going in becomes clear, you might decide to make this sentence its brief, if it more accurately conveys what you want from it. You can then feel free to change those first card properties if needs be.

Expansions: it can be helpful to brainstorm here. Have the expansion name in the middle, with the playstyle themes branching off it. Off of these write different related concepts; you should be able to identify a concept linking each theme, so put a line from each of them to it. Then note on how to imply each concept with Dominion mechanics, and if any of these are linked to other concepts somehow draw that on. Then, if you have any ideas for cards or your own mechanics, connect these onto the map. Keep thinking of links from one part of the map to the other and you will find coming to briefs for individual cards easier: this map represents the interactions and the very heart of the expansion, so very useful (just don't let your friends see it!). Keep in mind it's good for some cards to not interact well, so you define different strategies.

Playtesting

This is where you prove the quality of your idea. A test has been defined as measuring a subject against a standard. Your design ideas are the subject, and the standard is the plethora of official cards that exist and the average game that those cards make. The impact on your target audience and how well it fits into the average game (its balance) is the test. In other words, you're checking the last 2 big points on the spec of each of your cards, balance and dissimilarity, whilst confirming the first 2 from your imaginations, how interesting and easy to learn they are.

This is not going to be an easy section to write, as every possible design is going to need a different test. You're going to have to do some thinking yourself. Here's where the how to test column on the spec of each idea comes in. For balance, think about how you can use it to make a powerful winning deck, noting down what other (kinds of) cards would be needed (don't forget any synergy with itself!). For positive experience, note down how you imagine the card to be interesting, in what situations. For playing differently from official cards, write down all the ones that share similar functions, if there are any. For easy to learn, beyond the one-quick-sentence rule there's only one thing you can do: playtest with your play group. Text size is simple, as explained just below. Any other points you have will either already be met in previous stages or be tested at the same time as the big three. If not, you can probably work out what to write.

Preliminary Testing

You can probably do this by yourself; You may not need to if you've had friends all the way through your project, and that's of course fine, testing everything together can be fun. But if you're doing the project by yourself, there are some tests you can do first before showing the cards to your friends, to make the experience better for them.

You want to make prototypes of each of your ideas and simulate games to yourself. They're only prototypes - you don't need to go fancy with them! Writing them out on pencil and (card-sized) paper lets you make any needed changes. Then, you can set up a game as normal, adding whatever your design requires, and use any kingdom pile or pile of blanks and put the paper over the pile. You have to remember that any kingdom pile you use like this isn't doing what it normally does, which can be tough at first but you get used to it. An easier but costlier alternative if you sleeve your Dominion cards is slip paper prototypes in all the cards of the substitute piles.

You will also need a counter or somewhere to keep a tally, to count turns.

Generic Tests & the order you do them in

These are generalized tests; don't do them if you don't care about their result - after all, your design spec is your project.

Text size test

Open up the card generator, and type in your card's instructions in the Description box. How easy is it to read on the generated mock-up? Simple; you don't need to do anything else here.

The feel test

You don't need to count the turns for this. Take your idea and put it in a kingdom with cards you know will combo well with it.

How does it behave? Actually playing with the card can reveal things your imagining it couldn't see, which may make it stronger or weaker than you thought.

How exciting does it feel when it's in its element? It may not necessarily excite you, but can you imagine it exciting your audience? Can you identify ways it could safely be more fun? Also, how easily are you playing it out? If it's complicated or slow, how can you speed it up or simplify it without deviating from the brief?

Next, check how exciting it is in a couple of random games: is it nice to analyse at the start of each one? Ignore the novelty of it being your own idea, that's not the excitement you're identifying. If it isn't an interesting process, that suggests your idea is either too open or too narrow in functionality, missing the sweet middle ground, or it's niche but too weak or dull when it's good.

For expansions. once you have 10 or more individual card ideas for your expansion, put them all together in a game and get the feel of the interactions going on. This will be better if you tested them all individually first. Try to have a fresh mind for it, and play them as best you can; now sure, it's giving you an advantage over your friends, so by all means save this for when you're with them if you wish. But the point is, see if you're thinking along the lines of the playstyle themes of your expansion. You could easily come across some strong combos in the process; note these for the later speed test.

The Comparison Test

Only do this if your idea is similar to official ones; if it's utterly unique, you can't compare it to anything. You're aiming to check for balance by putting it against the official cards you know are balanced, and how different it is to play.

Take it and those that share similar functions and put them against each other in similar deck strategies. Simulate a 2-player game where one uses your idea. Unless a card in the game needs the deck to be as normal, you can take the shuffle randomness away from both sides by flipping each deck over, and when you draw a card pick any from the deck. See if you're satisfied with how different the feel of playing each deck is.

Which one is winning out, and why? If you don't see any reason within the mechanical differences of your idea, play the game through again in case your execution could've been better for either side or if turn order was a factor. If it's only a slight win, see if reintroducing shuffle randomness makes any unexpected distinct difference. If one is definitely winning more, really keep trying to pinpoint any reason why; sometimes it can be a very deep matter.

The Speed Test

How quickly can your idea make a deck that gets to a win condition? Too fast and it's imbalanced. Take the same combo cards you had for the feel test, take your method of counting turns, and flip the deck over to avoid shuffle randomness if you can. Think which game end method is best for your combo's strategy, and simulate an opponent if player interaction is needed. Run the game with the best possible card drawing, adding 1 to the count after every round of turns is finished.

If you're going for Provinces, the turn threshold that indicates balance will vary depending on how many different cards are in the combo, not including the base cards. If you have 2 kingdom cards, getting 4 Provinces after turn 12 is safe; if 3, 4 provinces after turn 10. You might justify quicker rates as balanced if the cards in the combo are very niche and weak overall (an example is Beggar with Guildhall), since it will rarely come up and very few different cards could replicate it. If you can find a combo that gets them faster using 4 or more cards, that's fine; it shows the potential your idea has, and the chances of all those cards appearing in the same game is slim. If you start the game with a $5/$2 split of money on the first 2 turns, that has about 11% chance normally; you might justify a stronger combo because of this, or disqualify it if you want to avoid that narrow chance deciding games.

If, though, your idea aims to get VP in its own way to win, make a kingdom that helps make it strong enough, and run it against a deck gaining just Provinces. Can it win? In how many different kingdoms could it win? You need it to win only some of the time, and you're aiming to figure out how often and get to a satisfactory rate.

If you need to test out a 3-pile ending, do this with others, as that's the only way to truly simulate it; get the actual mentality of different people rather than trying to imagine them, as you could easily end up biasing their decisions to the outcome you want.

Tweaks

Your solo testing may reveal some needed improvements. Try to first think about tweaks, the smallest changes you can make, so you don't interfere with the thoughts behind the previous stages of the process too much. Test these out, and if there are still issues think about bigger variants, perhaps at different costs and power levels. All this testing may seem arduous at first, but with time you can add to your design sense as described at imagining your ideas, so you may be able to lessen this part of the process.

Using the Variants subforum

Here you can call upon the help of other experienced Dominion players and designers at any stage of the design process. Outside perspective can be extremely valuable. What's generally appreciated is that you start your own thread for everything to do with all your ideas, or one separate one for each of your expansions. You'll probably also get more response if you post design ideas up rather than just your situation or brief, even if you feel the ideas are bad (admit it if so); ultimately design work is yours to do, and ready-made ideas are a more interesting read. That's why I've put this section under testing.

People may upvote your ideas. That's great of course, but just be clear on what that means: a lot of upvotes shows your idea gives a good first impression, not necessarily a good overall design. It has the exciting factor, but there could be deep underlying problems that people don't see at first. Conversely, a few upvotes or none at all doesn't necessarily mean your idea is bad, imbalanced or boring; its interest could be subtle and more apparent when actually played with.

You may get feedback replies. Again, this outside perspective can be just what you need, and things can be picked out that you missed. Be grateful and be open to what they say. To improve the quality and relevance of feedback, you might mention your situation, the idea's brief and extra points besides the big four in its spec (they're generally assumed; so is being playable in any kingdom, so if you're making an expansion to be played by itself say so), so people get on your wavelength. Mocking up your ideas with the stickied card image generator makes for an easier read (link images to your thread using an image hosting site like Imgur), but it's optional.

Playtesting with your Group

In pure testing terms, the principal advantage here is the outside perspective of your ideas in gameplay, and the reality of different players. Though of course, having fun is the bottom line of board game sessions, and you have to respect that. Set up a game as normal for the group (whatever you do when making an all-official kingdom, don't deliberately select the combo cards like you do with solo tests), making things seem as natural and relaxed as possible. You could either watch them play and observe critically your idea in action or join in and try to treat it like an all-official game, whatever the group's comfortable with. There are testing advantages both ways; the former is like an enhanced feel test, whilst the latter helps you to see the card as if it were official and if it fits in amongst them.

But before anyone jumps in thinking out their strategy, they need to know what the new cards are doing. Here's the test for how simple they are: get them to explain what your ideas do! If they can, your ideas cleanly pass. If you need to chip in with some explanations or rules errata for specific interactions, ask if it makes sense and hope for a unanimous yes, then play through the game and see if anyone asks about those rules again during it. If they don't, your idea may count as a pass, and seeing if they remember when you play it during a later games session will be the indicator. The outcome of this test may or may not identify changes to make depending on how important simplicity is to you, just as long as every game doesn't become an academic exercise.

For the first game or two you're looking for similar things to the solo feel test. Get feedback on how they feel about analysing it for strategy, and any other first impressions they get. As the game goes on and your idea has had a couple of uses, how are they feeling about playing with it? Extra things could be picked out besides your own testing, and more crucially your audience itself is speaking. Later on, ideally in later games with the idea, you want to check for balance issues: How quickly are piles emptying? Are games any faster or slower than expected or liked? How often is the card relevant to a winning strategy? Too often? Are player interaction effects favouring one person too much? Why?

Final Outcome

Once all the stages of the process have passed, the spec is as ticked off as it can be and your audience like the card or expansion and can see it just like an official one, it is done, ready to be enjoyed for however many games to come. How are you going to materialise it?

You could keep things as paper prototypes to save on money if your play group agree, or make things more glamorous and print them out nice on paper to sleeve, or even order real cards from a printing company. I'm no expert here, but I can say that the Dominion card size is European/Skat, 59x90mm, not bridge or poker size. Also see Printing & Layout.

Online, you can present finished ideas on this forum so others can see and play with them. As yet, the only real way to play fan cards virtually is with Tabletop Simulator, which isn't as smooth as ShuffleIT. You have to buy it, then organise meetings with players from around the world since there's no AI opponent option. We're almost certainly not going to see fan card implementation on Dominion Online. Someone could make an app, but to make it shareable with others you couldn't have the official cards on it as that would need Dominion Online's and Donald X's consent.

In any case, if you're using internet images for your card illustrations, carefully find the artist's name and put it at the bottom left of your mock-up, and check the image is free for non-commercial use; if it's from an art-sharing website like Deviantart or Artstation or from anywhere else where you know the artist is still alive, you should first ask for consent to use his or her work, as this avoids any potential legal issues.

Testing Tools

Project management tools like HackNPlan or Trello are super useful for tracking what needs to be done on a design, organizing ideas, organizing expansions, collaborating without users, and are free to use and can even incorporate things like image hosting directly into them.

However, you don't need to use them - Donald X. uses a text document and sometimes a spreadsheet and his turn out fine.

Common Pitfalls

The card ideas in this section come up frequently and are generally considered weak or broken for reasons that are not always obvious. I'll try to list these here and explain the problems with them. Again, though, keep my opening paragraph in mind. Do what you think will be fun, and if it's an idea on this list, so be it. But if you do, it's worth understanding the problems you're liable to face.

Reaction Pitfalls

Reactions can be revealed an infinite number of times when their needed event occurs, even after a new copy of the card enters your hand during the reaction (like with Caravan Guard). You need to either make how many times you reveal it not matter, or move it from your hand so you can't reuse it. If the reaction can't always trigger in every game, add something on that makes the card always useful. Making an on-play effect non-terminal (not be an Action without +Actions) lets several copies be added to the deck comfortably so the reaction will more likely and/or more often trigger; cantrip (Action with +1 Card +1 Action) even more so.

Mirror Force

Consider a reaction that harms the attacker, in particular reflecting the attack. This kind of idea comes up a lot. Sometimes the reaction is that the attack is reflected back on the attacker; at other times, some other form of harm befalls the attacker. Also variable is whether or not the attack still goes through to the reactor or not.

The basic problem with these kinds of reactions is that they make people afraid to play attack cards in the first place. And if they don't want to play attack cards, they don't buy attack cards. And if they don't buy attack cards, you won't have any need for your reaction card, either. The end result is that both the attacks and the reactions are left on the table.

There are more nuanced problems, too. Here's Donald X. on the subject:

As I usually tell people who want to show me cards, the obvious ideas are obvious to me too, and I had a big head start. For example Richard Garfield suggested 3 cards while he was playtesting Seaside. One was already in a set and has survived; one was already in a set but currently isn't in one although I have an idea for fixing it up. The third card was the reaction that reflects the attack, which I had had suggested so many times that I had already written up an essay on why it doesn't work.

The problem with defenses that attack is that, in 4-player games, there's a 1-to-3 ratio that goes the wrong way relative to the buying decision.

Let's consider 3 cards:

Point Eater. An attack that makes each other player lose 1 point. There's no Curse card involved; we'll track these points on a scoring track. I'm doing this to keep the analysis simple.
Revenge. When another player plays an attack card, reveal this to make them lose 1 point. It doesn't stop the attack. It only works for you once per attack, one way or another.
Moat. As-is.

I am just considering 4-player games here, which is where the problem is at its worst.

I play Point Eater. Each other player is down a point. Or, from my perspective, I'm up a point.

You Moat my Point Eater. For you, that's worth a point - you were going to lose a point, but now you don't. For me, that's -1/3 points. I make two out of three opponents lose a point, which is roughly 2/3 of a point of a benefit. It's rough because, who knows, maybe two of the players suck and I only care about the other one; if that one Moats I break even and if they don't I'm up a point. But in general, it's not like that; I am more or less still up 2/3 of a point when just one player Moats. So again: The person who decided to buy Moat makes a point here - they would have been down a point but are not - and the person who decided to buy Point Eater is still up 2/3 of a point after the Moat. Both cards still reward their players for buying them.

You Revenge my Point Eater. For you, that's worth 1/3 of a point - one out of your three opponents lost a point. For me, the entire benefit of my attack is gone - I break even rather than being up a point. The person who decided to buy Revenge just got 1/3 of a point of benefit; the person who bought Point Eater got nothing. Revenge is a weak investment and Point Eater is horrible. Of course if this means no-one buys Point Eaters then Revenge is useless.

See, it's this 1-to-3 ratio. In the wrong direction.

We could make Revenge three times as powerful - the attacker loses 3 points. Then playing Revenge is worth a point, like playing Moat. Being on the receiving end means losing 2 points net. Attacking is really unattractive in this situation, while defending is just as good as it is with Moat. It's even worse if, as in this example, Revenge is cumulative. Everyone else Revenges and you end up down 8 points. If everyone had Moated, you would have broken even.

Or, we could make Revenge one third as powerful - the attacker loses 1/3 of a point. Then being on the receiving end is just like having your attack Moated - you are back to getting 2/3 of a point for your attack. Playing Revenge is pointless though - you are only up 1/9 of a point. You could make the rest of the card good enough that this was playable, but you would completely ignore the defensive part when deciding whether or not to buy this.

So that's the deal. You can't fix the problem by tweaking the cost of Revenge; you still have the bad ratio. The one thing you can do is change the ratio; for example, Revenge could make every opponent lose a point whenever any opponent attacked. Then it's an attack that your opponents have to enable. Which is not necessarily out of the question, but isn't super sexy.

Non-terminal Reactions

If you create a non-terminal reaction, it's important to think through the ramifications. In particular, consider drawing non-terminal reactions very carefully. The issue is that making reactions non-terminal allows a player to stock up on them and thus pretty much always have one in hand when needed. Imagine adding a Moat-like reaction to Laboratory. You could buy them all up without harm to your deck, render attacks useless on virtually every turn, and still have a strong deck in its own right.

This problem is not insurmountable. The Reaction effect doesn't have to be an "attacks stop dead" effect like Moat has, and/or the Action component doesn't have to be as strong as Laboratory. But if you contemplate a non-terminal Reaction card -- again, especially drawing non-terminals, which do little or no harm to buy en masse -- consider the ramifications to the gameplay if one or more players decide to spam them.

Revealing Multiple Times & Ways to Defuse it

A subtle but significant rule about Reaction cards is that they can be revealed an unlimited number of times in response to any single event. Many fan Reaction cards aren't designed with this rule in mind. Consider this Reaction card: "When another player plays an attack card, you may reveal this from your hand. If you do, +1 Card."

With such a card, the moment someone plays a single Witch, I can reveal it as many times as I need to to draw my entire deck and discard pile into my hand. The official Reaction cards don't have this problem because they either do not stack (Moat and Secret Chamber, for example, don't do anything the second time that they can't do the first time) or cannot be reused (Horse Traders gets set aside when revealed).

If you have a Reaction effect that could stack if the card is revealed repeatedly, you can solve this problem either by using the Horse Traders mechanic of having the card set aside and returned to your hand later, or you can require that the card is discarded when revealed.

I'm sure these aren't the only viable solutions, but avoid special-case card text like, "You may only reveal this once per attack." The reason is that then it's hard for other players to account for whether you're revealing the same Reaction card multiple times or different copies of it in succession. This is especially true when you also have Secret Chamber, which could potentially rotate different copies of your other Reaction cards in and out of your hand

Reactions to things Other Than Attacks

Let me be clear: This is not a bad idea. There is probably a lot of design space still unexplored for Reactions that react to things other than attacks. The Dominion rules specifically allow for Reaction cards to be able to potentially react to any number of different kinds of events. But a word of caution: If you create a card that reacts to an event that no official Reaction card reacts to, think that through. A bad decision here could severely bog down the game.

For example, imagine the following card: "When another player plays a Treasure card, you may reveal and discard this card from your hand. If you do, the other player trashes the Treasure card immediately."

Here's the problem: Do you really want all players to have to wait, every single time they play a Treasure card, to see if anybody is going to play this Reaction to it? Without such a card, players will often lay their Treasure cards down all at once, which keeps the game moving quickly. But with such a Reaction card in play, it's strategically disadvantageous to do this, as then the Reactor will be able to make a more informed decision about which Treasure card he'd like to trash with it.

To date, the existing Reaction cards only react to events that would require that player to do something anyway. When someone plays Militia, there is already a natural pause in the game to wait for the other players to discard down to 3 cards in hand. The natural pause allows for the timely revealing of a Reaction card, like Moat, and not slow the game down any further. Similarly, Watchtower activates when the player holding a Watchtower in hand gains a card -- another moment in the game when the Reactor would be expected to act anyhow.

I'm not suggesting that Reaction cards should ONLY react to events that cause the Reactor to act. But they should probably only react to what are already natural breaks in the game.

Attack Pitfalls

Because attacks are one of the major means of player interaction in the game, there's no point making an Attack that kills the fun. Put yourself in the victims' shoes and see if it's interesting to play against; no attack should ever be able to forcibly give them a turn of doing nothing (by itself or when put with other cards), it should be possible to work around it in the absence of Moat variants, and it should make shuffle luck as little of an issue as possible (Knights are about the furthest stretch). Add a self benefit to it, so there's good reason for a softer player who dislikes Attacks to still want to get it; but think of the attack first, then the bonus and cost that best fit. If you add drawing cards, the attack can be launched more frequently as you draw it more often.

Trashing Attacks

An example of this is "Every other player trashes the top card of his deck." Donald X. frequently mentions this being a bad idea. The problem is that it's too swingy. One person loses a Curse. The next loses a Province. Unless a very swingy, very random game is what you're going for, you need to correct for this variance somehow. And then, even if you do, such cards usually aren't very fun. Players like to build up their decks. They get frustrated at seeing them regress.

The closest an official card comes to using this idea is Saboteur, which corrects for the variance by allowing the player to gain a replacement card whose cost is determined by the cost of the trashed card. Even with this correction for balance, it's one of the least popular cards in the game.

Stacking Attacks

"Every other player discards a card" is an example of such a card. By itself, it's fine. But if it gets played multiple times -- which, even in a kingdom without a Village or Throne Room, can happen easily in a 4-player game -- then the game can degenerate into a state where players discard most or all of their hands all the time and can't do anything.

Many of the official Dominion cards are great examples of how to circumvent this problem. Notice that Militia doesn't read "discard two cards" but rather "discard down to 3 cards." Torturer does say "discard two cards" but allows a player to take a Curse instead. Sea Hag has you discard the top card of your deck to prevent five Sea Hags from obliterating your next turn.

Cutpurse does hurt in multiples, but its effect is limited to how many Copper you have in your hand. The damage multiple Bureaucrat cards can do is similarly constrained to how many Victory cards you have in your hand, and the "gain a Silver" clause of Bureaucrat cleverly dilutes a Bureaucrat-heavy deck, so that multiple Bureaucrats aren't likely to be played repeatedly throughout a game.

The bottom line is you don't want to have an attack so strong that it can, by itself or stacked, completely ruin the next player's turn. Otherwise you can wind up in a game state where one player is locked out of being able to make any meaningful progress.

Targeting & Political Attacks

By purposeful design, Dominion doesn't have attacks that target specific players. Many Dominion players appreciate the lack of politics in the game — that is, the inevitable over-the-table negotiations and protests that result whenever a game allows a player to choose a specific opponent to target — and thus may not appreciate a fan card that opens that door. That said, there is not necessarily anything broken about having targeted attacks in Dominion, so if that's what you want to do, go for it.

Donald X on the subject:

Dominion always had everyone-but-you-style attacks, and the reason it did was because that's what I do in all my multiplayer games that have attacks (that don't have some more game-specific solution). It was automatic. It did not involve any special calculations or testing for Dominion specifically. And then it worked because of course it works, it had already worked in all those other games. This comes naturally from making games at all. You make a game. It allows for directed attacks. Who do they attack? Man, you designed it. You must be the one who knows what's going on. They attack you. Of course it also comes from evenings spent whining about who gets the robber, man, Tom's winning, put it on that ore why don't you, wtf, don't trade with Tom, are you nuts, he's winning I tell you, look he's just about to get the longest road. I don't see any reason you couldn't make a game like Dominion with directed attacks. Some people like spending the evening whining about who not to trade with - it takes all kinds - and there's nothing about "your game state is stored in a deck of cards" that defeats that. I personally don't like those games and so Dominion isn't one of them. But if political games are possible at all then you can also make a political deckbuilding game. I don't agree with some of the other stuff you said either, but it's not like I want to talk about what exactly is possible on a Dominion card. And what, I'd just as soon have people making up directed attacks for their homemade cards; since I won't be doing those, it stops us from overlapping.

Attacks that offer no benefit

Like almost everything in this list, this is not a firm rule. But before you create an attack card that ONLY harms other players, consider that of all the official cards, there are only two Attack cards that don't also provide some form of benefit to the player. These are Sea Hag, which is so strong for its cost that any additional benefit would overpower it; and Saboteur, which would be even more unpleasant than it already is if there were any additional incentive to use it. Even attacks as brutal as Mountebank, Witch, Ambassador, and Ghost Ship provide additional benefit to the player. Besides that benefit being necessary to achieve forward movement in the game, they also ensure that, if the attack portion is blocked by Moat, the attacking player hasn't utterly wasted his action.

All I'm getting at is that if you create an Attack card with no benefit, make sure the decision not to include a benefit was a conscious and considered choice and not just something you overlooked.

Gameshaping

This section deals with cards that very drastically shape the game they're in. This isn't to say this is bad per se — official cards like Chapel, Baker, and any of the Heirloom cards do this as well — but these are things to be mindful of when designing a card.

Power Cards & Drawbacks

This comes up a lot, perhaps more than any other idea on this list. Examples are numerous. Basically you invent a cheap but powerful card and attach a negative penalty to try to balance it. On the surface, this idea presents an intriguing dilemma to the player: Do you take the hit to your score in the hopes that the extra power will enable you to overcome the deficit?

The problem is that there is essentially no way to make such a card balanced. In a kingdom where trashing is possible, the correct play is probably to buy these cards, reap their benefits, and trash them before the game ends, circumventing the penalty entirely. To balance the card in such a kingdom, the penalty would have to be quite steep, to offset the likelihood that the card will be trashed before the game ends. But if the penalty is steep enough to balance that situation, it will be way too steep in kingdoms without trashing available, as then the VP penalty would be too great to risk.

Many people try to correct this problem by adding a clause to the card such as "This card cannot be trashed" or "If this card is trashed, place it in your discard pile instead of the trash pile." This kind of special-case rule rubs me wrong (there's a section on special-case rules later), though it might be workable in this case. Another workaround people use is "When you buy this card, gain a Curse." Or, since the Curse pile can run out and gained Curse cards can be trashed, the concept of a "curse token" is employed: "When you buy this card, gain X curse tokens." A curse token would be worth -1 at the end of the game, similarly to how Prosperity's Victory Tokens are worth +1 at the end of the game.

Regardless, these solutions still come up short, although they're improvements on the original idea. The problem is that a power card can't be balanced with a fixed cost, for the simple reason that totals vary wildly from game to game, depending on the board. Dominion games can be won with 5 points and lost with 100. The difference between scores can be very small, meaning a -2 penalty could be decisive, or very large, making it insignificant.

A counterargument to this is that one of the basic strategic principles of Dominion is recognizing that every card is good in some situations and bad in others, so a card that is powerful sometimes and weak at other times is no problem at all. But this kind of card seems to be usually either dominant or suicidal and only rarely in between.

The best solution seems to be to cause a penalty to be incurred upon each USE of the card, rather than merely on the purchase of it. Then the penalty is directly proportional to the benefit you get from using it. In games with heavy-trashing, where the card would be used more often, the penalty is steeper. In no-trashing games, where the card would be used less often, the penalty is smaller.

Seemingly the two best ways to incur a penalty upon use of the card are (1) "Gain X curse tokens," and (2) "Gain a Curse. If you do...." The former incurs an irreversible VP penalty. The latter puts a stop to free power plays when the Curses run out. Both deal damage in proportion to the use you get out of the card.

Trash Picking

When cards are trashed, they're trashed for a reason. A fan card that does something like "Gain a card from the trash pile" is going to be useless most of the time, because even if there are trashers in the kingdom (and there may well not be), who want a Copper, Estate, or Curse?

If there are trash-for-benefit cards in the kingdom (like Salvager, Apprentice, Bishop, and the Remodel family), then you might find something good in there, but this will only be a small minority of boards. And within that minority, there's a good chance the card will be brokenly powerful, and/or players will be dissuaded from using the trash-for-benefit cards on good cards in the first place.

Rogue, Lurker, and Graverobber retrieve cards from the trash, but they also put useful cards there to be retrieved at a later time. The balance is extremely delicate; any card that retrieves cards from the trash should be carefully tested.

Indefinite Duration

There is nothing inherently wrong with this idea, but a minor point: Usually this kind of idea is proposed with a new card type of "Permanent" or something. If the card otherwise behaves like a Duration card, then just call it a Duration card instead of inventing a new type. According to the Seaside rules, Duration cards stay out until the last turn in which they have an effect. Although the specific Duration cards in Seaside all get discarded after the following turn (except for a failed Tactician, which gets cleaned up immediately), the Duration type itself allows for a card to remain out for any arbitrary number of turns.

As of Renaissance, there are two cards that do this - Hireling and Champion. Both involve opportunity cost to obtain - Hireling is terminal, and Champion requires climbing a Traveller ladder to get.

Projects and events like Pathfinding can also be thought of as this, with an opportunity cost of a Buy + some sum of money.

On Terminality

The presence or absence of +Actions might be the single most defining characteristic of an Action card. Two versions of the same card, differing only in one having +1 Action and the other not, will likely play wildly different from one another. It's not the differing number of +Cards, for example, that distinguishes Smithy from Laboratory.

There is no firm rule concerning what kinds of Action cards should be terminal and which non-terminal. That decision is largely subjective. However, many fan cards include +1 Action when they might be more interesting without it. Make sure you consider the gameplay ramifications both ways. The right choice will be the one that makes the game's strategy more interesting, not necessarily the one that makes the card more appealing to purchase and use.

Sometimes the lack of +Actions is best. Consider how much less interesting Courtyard would be if it provided +1 Action (assuming its price was adjusted to compensate). The strategic feature of the official version of the card -- being able to save a dead Action card for the next turn -- would be destroyed.

On the other hand, sometimes you need +Actions to make the card work. A terminal version of Minion would be cute but weak; certainly not a card that a whole strategy could be built around.

Adding +Villagers (or, in Capitalism games, +Coin) is another way to make a card non-terminal (consider Patron) - then the player can decide whether they want to have the card be the last thing they play or not. However, giving Villagers willy-nilly may destroy the gameplay balance for more kingdoms than you'd like, rewarding stocking up on Attacks and terminal actions instead of building a well-thought-out deck.

Again, though, the distinction isn't always clear, and there isn't always one right answer. The important thing is just to consider the matter and make a thoughtful decision.

Golden Deck

Designing cards that award victory tokens is a trickier challenge than it seems. The reason is that you have to be careful not to allow a game to devolve into a game state where the optimum strategy for all players is to forego buying victory cards in favor of playing and replaying their victory-token-earning cards. Then the game never ends.

Of the three official cards that award victory tokens in Prosperity, two of them are tied to finite resources. Goons only awards victory tokens when you buy a card, which ensures that sooner or later the game will eventually end normally. Bishop awards tokens by trashing cards, which indirectly ensures the same thing -- if you don't buy cards, you won't have cards to trash.

Monument is the exception. In theory, if all players wind up with hands consisting of King's Court-King's Court-Monument-Monument-Monument, you could indeed wind up in an unending game state. But this doesn't really happen in practice, probably because of two things: one, Monument being a terminal makes it difficult to spam; two, it offers $, which encourages the purchase of cards.

The lesson these official cards teach us is that if you have a fan card that awards victory tokens, make sure the game can't wind up in an unending game state. If you can't prove this to yourself with theory (as is the case with Goons), then you'll need even more playtesting than usual to make sure.

Empires expanded on this a little bit - Chariot Race is a cantrip that can be a peddler+ but only if you get lucky; Groundskeeper is a cantrip that can double up on the Goons effect, but only when buying Victory cards; and the Gathering cards all have their own wind-down (i'm skipping Crumbling Castle because it's on trash/on gain and while I guess you could all collectively gain it then Ambassador it back to the pile, it seems unlikely that'd ever happen, requiring a good deal of cooperation in an otherwise competitive game); likewise, the landmarks that give tokens are all either finite supply or involve trashing/gaining, and so wind-down the game anyways.

Un-Dominion ideas

This is a catch-all for "the rest" of the worst ideas. In general, you want to maintain the following ideas:

Estates, Coppers, and Curses are junk cards. Things that remove their junk card status (Coppersmith, Counting House, Inheritance, Baron) are either terminal or an expensive and limited once-per-game, and the cases where you want a curse in your deck are limited, and you generally don't want more than one even if you want exactly one (Defiled Shrine, Museum).
The game ends when the Provinces run out or any three piles do
Infinite anything is busted
Maintain the gap between a -card and a -card.

Pro-Dominion ideas, in contrast:

Push your luck/Timing/I-know-that-you-know-that-I-know loops (Defiled Shrine, Wild Hunt, Tournament)
Competition for limited resources (Provinces, Artifacts)
Setting up for good turns (Lookout, Cartographer, Tactician)
Hurting other peoples next turns (Bureaucrat, Ghost Ship, Sea Hag)

Specialized Cards

Reference Limited Card Types

Examples of this would include "Gain an attack card", or "If you have at least three duration cards in play", or "You may trash up to 3 Curses", or "+$1 for every dual-typed card in your hand." The problem with these cards is simply that if they show up in kingdoms without any of these types present, the card is useless.

You can still make such a card work if the card also has behavior that is sometimes worth buying anyway. This is the case with reaction cards such as Moat, Secret Chamber, and Horse Traders. In the absence of Attack cards in the kingdom, these may still be worth having for their other functions.

Another way to solve the problem is for the card itself to force the intended condition. For example, a card that specifically references Potion cards is fine if it carries a Potion-based cost, as then, whenever that card would be present, Potions would be present also. Similarly, "Choose one: Trash any number of Curses from your hand; or every other player gains a Curse" would work, as then you wouldn't need a separate cursing card to be present.

Split piles, Heirlooms, and out-of-supply cards like Madman are other ways to force this synergy.

Resources Not Available

This is similar to the above. One example of this kind of card would be something that has "-1 Buy" on it. I actually think that's a really cool idea; the problem is that it's dead in a kingdom with no +Buy cards.

Another example would be Diadem, a card whose behavior is based on having unused actions. Donald X. experimented with Diadem as a regular kingdom card but found it to be a dead card too often, as in many kingdoms there are no sources of extra actions. (But it works fine as a Prize, where it's not taking up a whole kingdom pile.)

Still another example is a repeatedly proposed fan card that does only this: "+1 Card, +1 Action." Normally, this does nothing, as it merely replaces both the card slot and the action it uses up. But the justification for it is that it helps enable Conspirator, it lowers the price of Peddler, it can provide extra cards and actions with Throne Room or King's Court, it provides an extra unique card for Horn of Plenty, and so on. Yes, but the number of kingdoms with any of these cards in it is very small -- and in many of those, other cards will accomplish the same things. On the majority of boards, it's a dead pile.

Accountability

An example of such a card would be, "If this is in your hand at the start of your turn, you must play it immediately." The problem is that players can't be held accountable for following this rule. You'd have to have each player reveal his hand at the start of every turn, just so the other players can confirm that there is no copy of that card in hand to play. Otherwise it would be easy to keep the card in hand and secretly discard it underneath the other cards during clean-up.

That said, if you only intend to use such a card when playing with friends you trust, by all means, try an idea like this out. Otherwise, make sure your cards allow for accountability. Note Bureaucrat and Cutpurse, which provide such a mechanism.

Not all of the cards in the first edition base set are fully accountable - These were fixed in the Second Edition. Throne Room, Mine, and Moneylender all required you to do something with a card in your hand, but if you don't have a card of the correct type, they don't tell you to reveal your hand to prove it. (Treasure Map, from Seaside, is also like this.) Donald X. has expressed regret over Throne Room specifically; however, these cards are not problematic since the "fix" for them was to make their effects optional, rather than adding in accountability to the requirement. On a card whose effect needs to be mandatory (e.g., the aforementioned Bureaucrat and Cutpurse attacks), accountability is much more important, and you should make sure your own cards allow for it.

Census Cards

There are lots of different incarnations of this. And example might be, "The player to your left reveals the top two cards of his deck. +$ equal to the number of victory points he reveals." Another one might be, "All players reveal their hands. The player with the least total treasure gains a Curse."

Sidestepping balance issues in these specific examples that might jump out at you, these types of cards are unworkable because it's not always easy to quantify how many victory points or how much treasure you have in your hand. If only the base Victory cards are out, fine, but what if Gardens, Duke, Vineyard, or Fairgrounds is in play? You can't really calculate how much these are "worth" until the end of the game.

Treasure values are similarly nebulous. Technically, treasure isn't worth any coins at all until it's played. When a treasure card is played, only then does it yield some number of coins. In the case of the base treasures, this amount is always the same. (Well, almost. See Coppersmith.) But Bank, Philosopher's Stone, and Diadem vary, and Potion's yield isn't in coins at all.

Better approaches would be to count the number of Treasure or Victory cards, or look at the costs of those cards. In the latter case, you'll still have special cases in Philosopher's Stone and Vineyards, but many other Dominion cards (Salvager, Forge, Apprentice, etc) deal with (or ignore, in the case of Forge) Potion-based costs just fine.

Cost Comparison and The Almighty "Otherwise"

A thing to keep in mind with Dominion is there are three separate currencies to purchase things with - coin is by far the most common, but there is also Debt and Potions. Know how these compare (or don't) to each other.

Consider the last line of Chariot Race: "If your card cost more, + and +1 ." When you play that and you reveal an Overlord and they reveal a Silver, despite your card's price number being higher, it's in a non-comparable currency. You don't take the and . If you reveal a University and they reveal a Silver, it likewise doesn't cost more. You're comparing apples and oranges.

This is where the big Otherwise comes in. Rather than handling each case individually - greater than, less than, equal to, orthogonal to - you can lump a bunch of those together into a "Do this if X; Otherwise, do that".

Special Case Rules

Before using a special-case rule, be very sure you cannot achieve the effect you're after any other way. Even then, think long and hard about whether your special-case rule will cause conflicts with other rules or cards.

For example, you might want to have a powerful card limited by the clause, "You may only play one copy of this card per turn." Fine, but what happens when Golem turns up two copies of it? Which card's rules get broken?

A way around this specific example is how Crossroads works - "If this is the first time you play this, " - or how Tormentor works - "If this is the only card in play,".

Other special case rules include the trash clause on Fortress, caring about odd/even quantities on Idol, and which actions you can replay on Scepter or Royal Carriage. Consider using these cards as templates when you're trying to do something "off script".

Generally it's better for cards to work within the rules of Dominion than to override them. Even if a special-case rule poses no problem with the current set of official cards, you never know if something in a future expansion will cause a conflict.

the Discard Pile

You don't want to make cards that care about the order of the Discard pile. An example of this would be, "Look at the top five cards of your Discard pile. Put two of them in your hand."

Usually opening up Dominion's strategy space is a good thing; once in a while, not so much. It's no accident that no official Dominion card cares about the order that cards appear in the discard pile. The moment you introduce one that does, suddenly every player who buys it will have to think very carefully about how they perform every single clean-up phase, just in case they happen to draw that card in the next hand. This will dramatically slow down the game, and most of the time it'll still be wasted effort.

Card Costs

This is a big way in which learning the official cards well will help; you can develop a sense for what an appropriate price would be by comparing it with them. Most of the time how strong a card is determines its price, but sometimes there are cases for making a card cost artificially cheap or expensive to help its functions (like Chapel being cheap to be easily accessible, and Hunting Grounds being $6 so it can be remodeled).

Focusing on cost first before the rest of its abilities can make you quite cramped for flexibility, so it's usually better to leave it until last and fit it around everything else. An exception to this is if you're making a card to add more if a certain price point in an expansion. There are often variables you can adjust, like the amount of each +bonus, to better fit a certain cost for balance, so keep open to this.

Myths About Card Prices

Before I discuss how to price your cards, it's worth saying how NOT to price your cards, so you can undertake that task without any misleading preconceptions.

Myth: The Cost Scale Is Linear

Myth: Card costs are proportional to their strength

Myth: Given the above, card strength doesn't matter with respect to cost

Myth: Each functional component of a card has a cost; Add those up, and that's what the card should cost

Myth: Cards shouldn't cost

Pricing Your Cards

Step 1: Compare your card to official cards that are similar

Step 2: Calculate your card's cost based on its functional components

+1 Buy

+$1

The Second +Action

The First +Action

+1 Card

+VP tokens

Step 3: Playtest your card!

Copy Editing

Vanilla Bonuses

Wording

When To Use a Horizontal Line

VP vs +VP

2 means "This card is worth 2 at the end of the game." +2 means "Gain two victory tokens". Subtle difference.

Printing & Layout

Fonts

Templates

Card Creators

Blank Cards

Need more blank cards? You can buy individual sets of blank cards. Searching Google Shopping will probably turn up a few different places to buy them. I buy mine at the board game geek store.

Fan Card Creation Tools

Shard Of Honor's card template - a fork of VioletCLM's card creator with additional functionality added.
VioletCLM's card creator
thread discussing both card creators

Design Contests

Design contests for fan cards are run periodically by various users of the message board.

Card mock-up for Archivist made by jsimantov of Board Game Geek.

Dominion Fan Card Contest

In October 2011 user Davio organized a fan card creation contest.^[1] As motivation to receive quality entries, Davio offered a modest prize of an Amazon gift card. Davio received 20 entries and allowed the community to vote on the winner. The chosen winner was Archivist, a card designed by rinkworks.^[2] The card was an example of a single card engine, with the following card text:

Name: Archivist
Type: Action
Cost:
Card Text: +1 Action. Choose one: Draw until you have 6 cards in hand; or + and discard 1 or more cards from your hand.

To the surprise of the community, Davio had secretly contacted dougz and the card was playable for a limited time on Isotropic.^[3] This is the only instance of an unofficial Dominion card being playable on the public version of Isotropic.

Mini-Set Design Contest

As a followup to Davio's contest, rinkworks later launched a far more ambitious design contest. The second contest attempted to create a complete mini-set of cards, with every card in the set being designed, voted on, and fine tuned by members of the community. There was a full subforum dedicated to the contest on the forums.^[4]

Weekly Design Contest

A follow-up contest to rinkwork's Set Design contest, the Weekly Design contest was started by Doom_Shark; it has a rotating judging criteria and its host is whoever won the previous week's contest. It has been running since Sept 2018. Its winners are posted in the Weekly Design Hall of Fame.

References

↑ Davio, "Dominion Fan Card Contest", Dominion Strategy Forum
↑ Davio, "Dominion Fan Card Contest", Dominion Strategy Forum
↑ Davio, "Fan Cards On Isotropic", Dominion Strategy Forum
↑ "Mini-Set Design Contest Subforum", Dominion Strategy Forum

v . t . e Dominion Cards
Basic cards	Copper • Curse Estate Silver Duchy Gold Province
Dominion	Cellar • Chapel • Moat Harbinger • Merchant • Vassal • Village • Workshop Bureaucrat • Gardens • Militia • Moneylender • Poacher • Remodel • Smithy • Throne Room Bandit • Council Room • Festival • Laboratory • Library • Market • Mine • Sentry • Witch Artisan Removed cards: Chancellor • Woodcutter Feast • Spy • Thief Adventurer
Intrigue	Courtyard • Lurker • Pawn Masquerade • Shanty Town • Steward • Swindler • Wishing Well Baron • Bridge • Conspirator • Diplomat • Ironworks • Mill • Mining Village • Secret Passage Courtier • Duke • Minion • Patrol • Replace • Torturer • Trading Post • Upgrade Farm • Nobles Removed cards: Secret Chamber Great Hall Coppersmith • Scout Saboteur • Tribute Harem
Seaside	Haven • Lighthouse • Native Village Astrolabe • Fishing Village • Lookout • Monkey • Sea Chart • Smugglers • Warehouse Blockade • Caravan • Cutpurse • Island • Sailor • Salvager • Tide Pools • Treasure Map Bazaar • Corsair • Merchant Ship • Outpost • Pirate • Sea Witch • Tactician • Treasury • Wharf Removed cards: Embargo • Pearl Diver Ambassador Navigator • Pirate Ship • Sea Hag Explorer • Ghost Ship
Alchemy	Transmute • Vineyard Herbalist Apothecary • Scrying Pool • University Alchemist • Familiar • Philosopher's Stone Potion Golem Apprentice Possession
Prosperity	Anvil • Watchtower Bishop • Clerk • Investment • Tiara • Monument • Quarry • Worker's Village Charlatan • City • Collection • Crystal Ball • Magnate • Mint • Rabble • Vault • War Chest Hoard Grand Market Bank • Expand • Forge • King's Court Peddler Platinum Colony Removed cards: Loan • Trade Route Talisman Contraband • Counting House • Mountebank • Royal Seal • Venture Goons
Cornucopia & Guilds	Candlestick Maker • Hamlet Farrier • Stonemason Menagerie • Shop Infirmary Advisor • Farmhands • Plaza • Remake • Young Witch Herald Baker • Butcher • Carnival • Ferryman • Footpad • Horn of Plenty • Hunting Party • Jester • Journeyman • Joust (Rewards: Coronet • Courser • Demesne • Housecarl • Huge Turnip • Renown)• Merchant Guild • Soothsayer Fairgrounds Removed cards: Fortune Teller Doctor • Masterpiece Farming Village • Horse Traders • Taxman • Tournament (Prizes: Bag of Gold • Diadem • Followers • Princess • Trusty Steed) Harvest
Hinterlands	Crossroads • Fool's Gold Develop • Guard Dog • Oasis • Scheme • Tunnel Jack of All Trades • Nomads • Spice Merchant • Trader • Trail • Weaver Berserker • Cartographer • Cauldron • Haggler • Highway • Inn • Margrave • Souk • Stables • Wheelwright • Witch's Hut Border Village • Farmland Removed cards: Duchess Oracle Noble Brigand • Nomad Camp • Silk Road Cache • Embassy • Ill-Gotten Gains • Mandarin
Dark Ages	Ruins (Abandoned Mine • Ruined Library • Ruined Market • Ruined Village • Survivors) Spoils Poor House • Shelters (Hovel • Necropolis • Overgrown Estate) Beggar • Squire • Vagrant Forager • Hermit (Madman) • Market Square • Sage • Storeroom • Urchin (Mercenary) Armory • Death Cart • Feodum • Fortress • Ironmonger • Marauder • Procession • Rats • Scavenger • Wandering Minstrel Band of Misfits • Bandit Camp • Catacombs • Count • Counterfeit • Cultist • Graverobber • Junk Dealer • Knights (Dames Anna • Josephine • Molly • Natalie • Sylvia • Sirs Bailey • Destry • Martin • Michael • Vander) • Mystic • Pillage • Rebuild • Rogue Altar • Hunting Grounds
Adventures	Coin of the Realm • Page (Treasure Hunter • Warrior • Hero • Champion) • Peasant (Soldier • Fugitive • Disciple • Teacher) • Ratcatcher • Raze Amulet • Caravan Guard • Dungeon • Gear • Guide Duplicate • Magpie • Messenger • Miser • Port • Ranger • Transmogrify Artificer • Bridge Troll • Distant Lands • Giant • Haunted Woods • Lost City • Relic • Royal Carriage • Storyteller • Swamp Hag • Treasure Trove • Wine Merchant Hireling Events: Alms • Borrow • Quest Save Scouting Party • Travelling Fair Bonfire • Expedition • Ferry • Plan Mission • Pilgrimage Ball • Raid • Seaway • Trade Lost Arts • Training Inheritance Pathfinding
Empires	Engineer City Quarter • Overlord • Royal Blacksmith Encampment/Plunder • Patrician/Emporium • Settlers/Bustling Village Castles (Humble • Crumbling • Small • Haunted • Opulent • Sprawling • Grand • King's) • Catapult/Rocks • Chariot Race • Enchantress • Farmers' Market • Gladiator/Fortune Sacrifice • Temple • Villa Archive • Capital • Charm • Crown • Forum • Groundskeeper • Legionary • Wild Hunt Events: Triumph Annex • Donate Advance Delve • Tax Banquet Ritual • Salt the Earth Wedding Windfall Conquest Dominate Landmarks: Aqueduct • Arena • Bandit Fort • Basilica • Baths • Battlefield • Colonnade • Defiled Shrine • Fountain • Keep • Labyrinth • Mountain Pass • Museum • Obelisk • Orchard • Palace • Tomb • Tower • Triumphal Arch • Wall • Wolf Den
Nocturne	Will-o'-Wisp • Wish Druid • Faithful Hound • Guardian • Monastery • Pixie (Goat) • Tracker (Pouch) Imp Changeling • Fool (Lost in the Woods • Lucky Coin) • Ghost Town • Leprechaun • Night Watchman • Secret Cave (Magic Lamp) Bard • Blessed Village • Cemetery (Haunted Mirror) • Conclave • Devil's Workshop • Exorcist • Necromancer (Zombies: Apprentice • Mason • Spy) • Shepherd (Pasture) • Skulk Ghost Cobbler • Crypt • Cursed Village • Den of Sin • Idol • Pooka (Cursed Gold) • Sacred Grove • Tormentor • Tragic Hero • Vampire (Bat) • Werewolf Raider Boons: The Earth's Gift • Field • Flame • Forest • Moon • Mountain • River • Sea • Sky • Sun • Swamp • Wind Hexes: Bad Omens • Delusion (Deluded) • Envy (Envious) • Famine • Fear • Greed • Haunting • Locusts • Misery (Miserable/Twice Miserable) • Plague • Poverty • War
Renaissance	Border Guard (Horn • Lantern) • Ducat • Lackeys Acting Troupe • Cargo Ship • Experiment • Improve Flag Bearer (Flag) • Hideout • Inventor • Mountain Village • Patron • Priest • Research • Silk Merchant Old Witch • Recruiter • Scepter • Scholar • Sculptor • Seer • Spices • Swashbuckler (Treasure Chest) • Treasurer (Key) • Villain Projects: Cathedral • City Gate • Pageant • Sewers • Star Chart Exploration • Fair • Silos • Sinister Plot Academy • Capitalism • Fleet • Guildhall • Piazza • Road Network Barracks • Crop Rotation • Innovation Canal Citadel
Menagerie	Black Cat • Sleigh • Supplies Camel Train • Goatherd • Scrap • Sheepdog • Snowy Village • Stockpile Horse Bounty Hunter • Cardinal • Cavalry • Groom • Hostelry • Village Green Barge • Coven • Displace • Falconer • Gatekeeper • Hunting Lodge • Kiln • Livery • Mastermind • Paddock • Sanctuary Fisherman Destrier • Wayfarer Animal Fair Events: Delay • Desperation Gamble • Pursue • Ride • Toil Enhance • March • Transport Banish • Bargain • Invest • Seize the Day Commerce • Demand • Stampede Reap Enclave Alliance • Populate Ways: Butterfly • Camel • Chameleon • Frog • Goat • Horse • Mole • Monkey • Mouse • Mule • Otter • Owl • Ox • Pig • Rat • Seal • Sheep • Squirrel • Turtle • Worm
Allies	Bauble • Sycophant • Townsfolk (Town Crier / Blacksmith / Miller / Elder) Augurs (Herb Gatherer / Acolyte / Sorceress / Sibyl) • Clashes (Battle Plan / Archer / Warlord / Territory) • Forts (Tent / Garrison / Hill Fort / Stronghold) • Importer • Merchant Camp • Odysseys (Old Map / Voyage / Sunken Treasure / Distant Shore) • Sentinel • Underling • Wizards (Student / Conjurer / Sorcerer / Lich) Broker • Carpenter • Courier • Innkeeper • Royal Galley • Town Barbarian • Capital City • Contract • Emissary • Galleria • Guildmaster • Highwayman • Hunter • Modify • Skirmisher • Specialist • Swap Marquis Allies: Architects' Guild • Band of Nomads • Cave Dwellers • Circle of Witches • City-state • Coastal Haven • Crafters' Guild • Desert Guides • Family of Inventors • Fellowship of Scribes • Forest Dwellers • Gang of Pickpockets • Island Folk • League of Bankers • League of Shopkeepers • Market Towns • Mountain Folk • Order of Astrologers • Order of Masons • Peaceful Cult • Plateau Shepherds • Trappers' Lodge • Woodworkers' Guild
Plunder	Cage • Grotto • Jewelled Egg • Search • Shaman Secluded Shrine • Siren • Stowaway • Taskmaster Abundance • Cabin Boy • Crucible • Flagship • Fortune Hunter • Gondola • Harbor Village • Landing Party • Mapmaker • Maroon • Rope • Swamp Shacks • Tools Buried Treasure • Crew • Cutthroat • Enlarge • Figurine • First Mate • Frigate • Longship • Mining Road • Pendant • Pickaxe • Pilgrim • Quartermaster • Silver Mine • Trickster • Wealthy Village Sack of Loot King's Cache Loots (Amphora • Doubloons • Endless Chalice • Figurehead • Hammer • Insignia • Jewels • Orb • Prize Goat • Puzzle Box • Sextant • Shield • Spell Scroll • Staff • Sword) Events: Bury Avoid • Deliver • Peril • Rush Foray • Launch • Mirror • Prepare • Scrounge Maelstrom • Journey Looting Invasion • Prosper Traits: Cheap • Cursed • Fated • Fawning • Friendly • Hasty • Inherited • Inspiring • Nearby • Patient • Pious • Reckless • Rich • Shy • Tireless
Promo	Black Market • Church Dismantle • Envoy • Sauna/Avanto • Walled Village Governor • Marchland • Stash Captain Prince Events: Summon
Base Cards	Copper • Curse Estate Silver Potion Duchy Gold Province Platinum Colony
See also:	Second Edition • Errata • Outtakes (Confusion) • Fan cards • Card storage • List of cards (in other languages)