Sifter

A sifter is a card that draws and discards, in either order, or reveals/looks at cards from your deck with the option of discarding them, so as to cycle through your deck to get to more desirable cards. Many of these are non-terminal Actions, such as Warehouse, which allow you to draw cards and then force you to discard some as well. Sifters can increase or decrease handsize, depending on what additional role they take, if any.

A related class of cards are diggers, which "dig" through your deck for cards meeting some description and discard those that don't. Sifters differ from those by allowing you to choose which individual cards to discard.

List of sifters

• Cards which let you discard cards from your hand:
  • Cellar
  • Warehouse
  • Minion
  • Vault
  • Hamlet
  • Oasis
  • Storeroom
  • Young Witch
  • Inn
  • Embassy
  • Stables - Only lets you discard Treasure cards
  • Plaza - Optional sifter, Treasures only
• Sifters that are also deck inspectors:
  • Catacombs
  • Scrying Pool
  • Oracle - Top 2 cards
  • Spy
  • Navigator - Top 5 cards
  • Jack of all Trades
  • Ironmonger
  • Cartographer - Top 4 cards

Courtyard plays similarly to a sifter, though it requires you to top-deck rather than discard.

Strategy

Sifters, particularly those that give +1 Action, are most useful in trying to get two combo-ing cards to collide. The most extreme case is Treasure Map, but there are other cards that do best in combination with another card. Sifters are optimal for this because they usually draw more than terminal draw cards at the same cost, giving you more cards that could be what you're looking for, and since you're only looking for two cards, you don't care that you have to discard afterwards. All sifters are also quite nice with Tunnel, as they provide the much-needed discard outside of the Clean-up phase to gain Tunnel's Golds.

Terminal sifters are usually more useful in the context of an engine, or in big money strategies. Without village support, they are highly likely to draw Actions dead, given their higher draw, though this is mitigated by their discarding requirement. This makes them very useful for big money, as they can concentrate your Treasures in hand while skipping over Victory cards.