From DominionStrategy Wiki
Disappearing money is an informal term for non-terminal Action cards that give + but are stop cards. They resemble most Treasure cards in that they give + and reduce handsize when played, and any number of them can be freely played on a turn; but unlike Treasure cards they can be played from your hand before other Action cards are played which makes them relevant as payload in certain kinds of engines that do not work well with Treasures.
With sufficient terminal space, terminal Actions that give + (like Guildmaster) can work the same way.
 Engines which benefit from disappearing money
- Draw-to-x cards like Library, Cursed Village, Minion
- Tactician which typically prevents you from using Treasures on the turn it is played.
- Menagerie: unlike Treasure, you can have any number of copies of the same disappearing-money Action and play them all before Menagerie to create a hand with no duplicates.
- Engines that draw Actions much more easily than Treasures: Scrying Pool and City Quarter
- Diplomat: reducing your handsize first before playing Diplomat allows you to use Diplomat as a village.
 List of cards that can provide disappearing money
- Dominion: Festival
- Intrigue: Courtier, Minion, Pawn
- Seaside: Lighthouse, Fishing Village
- Dark Ages: Forager, Mystic, Squire
- Guilds: Candlestick Maker
- Adventures: Treasure Hunter
- Empires: Villa
- Nocturne: Conclave
- Renaissance: Patron
- Menagerie: Bounty Hunter, Coven, Paddock, Way of the Mule
- Allies: Sycophant, Merchant Camp
- Plunder: Mining Road, Shaman, Taskmaster
Oasis and Junk Dealer each draw a card but also remove a card from your hand, so they have the same effect on your hand size as if they were a stop card.
- Base: Poacher -- Only reduces your handsize if at least one Supply pile is empty.
- Prosperity: Clerk -- Is only non-terminal if it is in your hand at the start of your turn.
- Seaside: Sailor -- disappears from your hand on one turn to provide money on the next turn.
- Guilds: Plaza -- requires you to discard a Treasure or it doesn't reduce your handsize.
- Nocturne: The Field's Gift -- unreliable because it will only be revealed by a Fate card 1/12 of the time.
- Allies: Courier and Elder -- need to play a non-terminal stop card. In the latter case, a cantrip also works.