A trading card (or collectible card) is a small card, usually made out of paperboard or thick paper, which usually contains an image of a certain person, place or thing (fictional or real) and a short description of the picture, along with other text (attacks, statistics, or trivia). There is a wide variation of different types of cards. Modern cards even go as far as to include swatches of game-worn memorabilia, autographs, and even DNA hair samples of their subjects.

Trading cards are traditionally associated with sports; baseball cards are especially well-known. Cards dealing with other subjects like Pokémon are often considered a separate category from sports cards, known as non-sports trading cards. These often feature cartoons, comic book characters, television series and film stills. In the 1990s, cards designed specifically for playing games became popular enough to develop into a distinct category, collectible card games. These games are mostly fantasy-based gameplay. Fantasy art cards are a subgenre of trading cards that focus on the artwork. The game with the highest number of unique cards and one of the most successful is Magic: The Gathering.