As you progress through the game, several kinds of special Boost Cards will be unlocked. Once unlocked, these can be played at any time to help complete the current puzzle.

Cards are sometimes dealt from the deck, and can also be purchased with coins (by tapping that card's icon when you have none of that card in reserve), or from the Store as part of Bundle items (when available).

Please refer to the 'Boost Cards' section of the FAQ for details of each card.