Cards of Power

A form of Ancient Artifact, Cards of Power are small, rigid pieces of paper or cardboard which possess paranormal or magical powers. The abilities they possess vary widely from one narrative to another. In some works, they can summon creatures or monsters. In others, they are used to cast spells or as a Transformation Trinket. They are also often tarot cards and may use Tarot Motifs.

A subtrope is Ofuda, a Shinto talisman of protection.

Compare Death Dealer, when the cards are used as physical weapons.

For a version specific to video games, see Fight Like a Card Player.

Anime & Manga

 * Cardfight Vanguard: The cards allow access to another realm from which you can summon the monsters/characters (though you also need a special ability to use the cards in this way).
 * The Clow cards in Cardcaptor Sakura contain magical spirits and each card allows the main character to have to have access to various types of powers such as Playing with Fire or Making a Splash.
 * Hitomi Kanzaki from Vision of Escaflowne uses Tarot cards for what she thinks is ordinary fortune-telling. However, while she is on Gaea, her psychic talent actually creates the future she foretells.
 * Fairy Tail: Cana is shown capable of use her cards to create magical explosions, water geysers, scantly-dressed women and at least once is used to put a person to sleep. Sho usually throw them like shurikens but can also imprison people inside his cards.
 * Mahou Sensei Negima: When a mage and his partner form a Pactio, the partner receives a card that allows them to summon a powerful artifact, such as Asuna's fan/sword and Nodoka's magic diary.
 * Yu-Gi-Oh: Naturally, for an anime based on a card-fighting game. In that world, cards played summon a monster in a field that fights the opponent's creature.
 * Digimon Tamers: Takashi's Guilemon went through a card swiper and became real. Any other tamer could power up his digimon by swiping a card in his digivice.
 * In Magical Girl Lyrical Nanoha As, Chrono eventually gets a Storage Device Durandal, that has a card form when on standby.
 * Teana's Intelligent Device Cross Mirage in Magical Girl Lyrical Nanoha Striker S also has a stand-by form of a card.

Comic Books

 * Lucifer: The Basanos; a magical set of tarot cards with the power of prophecy (amongst other things), created by the angel Meleos. Not merely magical, but also sentient. The Basanos also have a few more Arcana than a standard Tarot deck, including several cards representing major angels such as Lucifer (as The Lightbringer, not The Devil).

Literature

 * In Roger Zelazny's Chronicles of Amber novels, the royalty of Amber uses Tarot cards for communication and teleportation.
 * Ian Watson's Warhammer 40000 trilogy The Inquisition War had The Emperor's Tarot; a special Tarot deck for use by Ordo Malleus Inquisitors to divine the future using their psychic powers. The cards had a link to the God-Emperor himself as well as being powered by the user; thus they actually had genuine precognitive ability. Each card was a screen, the images on which altered from Inquisitor to Inquisitor depending on their personality and also shifted to match situations; when Draco conducted a reading in Inquisitor, the Daemon card took the form of a Hydra and the Harlequin card took that of Zephro Carnelian.
 * The Imperial Tarot also crops up in Last Chancers and Ciaphas Cain.

Live Action TV

 * In three separate Kamen Rider series (Kamen Rider Ryuki, Kamen Rider Blade and Kamen Rider Decade), cards are used to give the heroes weapons. In the case of the last one, the hero also inserts a card into his transforming belt in order to Henshin.
 * Tensou Sentai Goseiger has the heroes insert cards into their Tensouder to cast spells.
 * In Bar Karma, the magic card deck shows three possible outcomes or "timelines" for its patrons, who wandered into the bar mysteriously, because their decisions will dictate the direction of their destiny. In most cases, many lives will be at stake in order for a patron to be drawn into the bar.

Tabletop Games

 * Dungeons and Dragons.
 * The Deck of Many Things. Beneficial cards in the deck could grant the person drawing them great wealth, magic items, high social position or even Wishes. A baneful card could strip away wealth, cause a powerful demon or devil to hate the character or even cause the person who drew it to be instantly and irrevocably killed.
 * Deck of Illusions: Throwing down a card will create an illusionary monster, with a different monster for each card.
 * Deck of Fortune Telling from the Ravenloft setting. When someone pulls a card out of the deck it will tell that person's fortune (future).
 * Quarter Deck: When a card is drawn and shown to an opponent, the opponent may surrender.
 * Sun Deck: Any card drawn from the deck will give off a bright light.
 * Tarot Deck of Many Things: Like the regular Deck of Many Things but with a Tarot motif. The cards have beneficial or negative effects depending on whether they're right side up or upside down when drawn.
 * Module X2 Castle Amber. In one room, the PCs can turn over special cards from a Tarot deck. Each card has a specific magical effect on the person who turns it over, such as The Moon (going insane), Death (make a Saving Throw or die), or The Fool (Feeblemind spell cast on character).
 * Deadlands: Hucksters are The Weird West equivalent of mages; their 'spells' are based around poker hands, in keeping with the significance of poker cards and hands throughout the game rules.
 * North Pole Publications' The Serpent Islands (a generic RPG adventure) had Ardol's Gateway Deck. These enchanted tarot-like plaques depicted various people or places. Intently gazing at the picture of a place would teleport the gazer to that place. Gazing at the picture of a person would open a Gate between the user and that person. Passage through the Gate was possible only with the permission of the person depicted.

Video Games

 * Magnus from the Baten Kaitos series are cards that are used to store the essence of objects within them. This allows characters to carry otherwise impractically heavy or cumbersome things and occasionally even intangible objects like "good times" or "chronic fatigue." These cards also form the basis of the game's battle system.
 * The early Persona games had monsters summoned from cards... though Persona 3 seems to favor pseudo-suicide as a method of demon-summon. For some reason Tarot-cards and related motifs are still hanging around in the more recent games, and influence what monsters you can create through fusion, among other things, but there's no indication that those cards are actual physical objects, rather than just a fanciful way of showing your progress with the various Links...
 * Triple Triad cards from Final Fantasy VIII can be magically turned into magic items and spells. Monsters drop them, and you can polymorph a critter to a card bearing its likeness.
 * Dungeon Crawl plays this straight: One item type is magical card decks with different themes such as destruction or escape.
 * Super Paper Mario has Catch Cards, one of several categories of collectibles for Hundred-Percent Completion. These can be collected either by finding them in certain shops or as treasure, or by throwing a blank card at an enemy and hoping it transforms into that enemy's likeness. The more copies of a particular enemy's card you own, the more damage you'll do against it.

Web Comics

 * Homestuck. The Midnight Crew's have playing cards that become weapons (and vice versa).

Western Animation

 * Jackie Chan Adventures used Japanese Hanafuda as scrying tools in its last season.