A trick deck is a deck of playing cards that has been altered in some way to allow magicians to perform certain card tricks where sleight of hand would be too difficult or impractical.

The Brainwave deck is a lesser-known deck which is gaining in popularity, it operates on a principle similar to that of the Invisible Deck, but has vastly improved on it. With the cards still in their box, the magician asks a spectator to name a card. The magician pulls the deck out and fans the cards face down, then spreads through the deck until a single face-up card is discovered, which turns out to be the spectator's card. For the grand finale the magician explains that he or she actually knew ahead of time which card the spectator would select, rather than having secretly turned it over during the performance. He or she then proceeds to prove this by turning the spectator's card over and revealing that the card in question features a different backing pattern than every other card in the deck, suggesting to the audience that the magician may possess powers of extrasensory perception.

An inverse handling of the Brainwave deck is the X Deck, originally invented by Jay Sankey and identical to the Invisible Deck, but with the odd cards having an X on them. Both decks are meant to convey the idea that the magician did not perform the intended effect through the use of sleight of hand.

These decks are used to force a spectator to select a particular card, which the magician already knows in advance. Such a feat can be accomplished using a regular deck and sleight of hand but with the aid of a forcing deck the trick is made self-working.

One of the simplest forcing decks is the "one-way forcing deck", where all cards are identical (with the possible exception of one or two at the top and bottom of the deck). When using this deck, the magician must be careful to prevent the spectator from seeing the faces of the cards. The below-mentioned Svengali Deck can also be easily used as a force deck, by forcing the choice of one of the twenty-six identical short cards.

A variant of the one-way forcing deck is the Monte Cristo deck invented by Henry Hardin, more recently published under the name Mastermind Deck by Chris Kenworthey. All the cards are the identical force card, but misindexed on the top left corner, so that the cards all appear to be different when fanned or spread. Any card can be selected, and rotating the deck before revealing the selection will always reveal the force card.

It is worth noting that such decks have fallen out of favor amongst professional magicians because of an increased suspicion amongst audiences regarding the use of gimmick props. Thus, they are rarely employed.^{[citation needed]}

The invisible deck is one of the best known card tricks. Joe Berg created the Invisible Deck in the 1930s, originally calling it the Ultra Mental Deck. Often mistakenly credited to Dai Vernon, Don Alan or Eddie Fields, the most-used presentation of an "invisible" deck of cards was invented by J.B. Bobo.