Supporter cards (Japanese: サポーターSupporter) are a classification of trading cards that debuted in English in the Expedition Base Set with the start of the e-Card Series, and within the P Promotional cards during the Web Era in Japan. Originating as a subclass of Trainer cards, Supporter cards, as well as Stadium cards, were elevated to equal level as Trainer cards with the start of the Diamond & Pearl Series. When the Trainer cards of Generation IV were reclassified as Item cards, the term "Trainer card" became an overarching term, while Supporter and Stadium cards joined Item cards and returned to subclasses of Trainer cards.
Supporter cards depict and feature people. Generally, the people are characters from the Pokémon games and Pokémon anime such as Gym Leaders and Trainer classes, though many are exclusive characters featured within the many themes created for the Pokémon Trading Card Game. Much like how Item and Stadium cards changed their colors to blue and green, respectively, Supporter cards are colored red. As the characters of the games and the anime change periodically, it is not uncommon for various Supporter cards from different Generations to share the same effects: for example, both the Generation III EX Series Supporter Professor Birch and the Generation V Black & White Series Supporter Bianca share the same effect.
Players are allowed to play only 1 Supporter card during their turn (unless a card allows them to play more). When they were first introduced, most Supporters were to be played next to the player's Active Pokémon and discarded at the end of that player's turn. The only supporter not to be discarded was Charon's Choice, who returned to the hand instead. With the release of the Black & White expansion, this practice was changed, and Supporters were to be discarded directly after being played. This was to allow players to retrieve it from the discard pile during the same turn if they wished.
A feature of the Black & White Series of the Pokémon Trading Card Game is that popular Supporter cards are reprinted as Full Art cards. Other than Full Art cards, Supporter cards typically do not receive alternate artworks. Occasionally, when the card is reprinted in a completely different Series or is reprinted and released through a special promotion, it may receive an alternate artwork. There are currently 173 different Supporter cards, though many have received multiple prints.