Gym Heroes

Gym Heroes, released on August 14, 2000, is the 6th set of 132 cards in the Pokémon Trading Card Game. Its symbol is an amphitheatre with a black stage and white tiers. Its name comes from the Gym Leaders it focuses around and how these first four Gym Leaders have relatively optimistic and carefree personalities compared to those featured in Gym Challenge. This set also introduced a card layout change, eliminating the flavor text and stacking the weakness/resistance/level to fit the Gym Leader's headshot/badge.

This is the first set to have Owner's Pokémon, the owners being the Gym Leaders of the various Pokémon Gyms around Kanto. While Sabrina and Blaine are also represented in this set, the most attention is paid to the first four met in the video games: Brock, Misty, Lt. Surge, and Erika. Each of their Pokémon reflect their favorite Pokémon types, as well as Pokémon they have been seen carrying in the TV show. For example, Brock specializes in the Rock-type, so a lot of his cards in the card game are Rock Pokémon. However, in the anime, he also carried a Vulpix, a Fire-type, which is also included in this set.

Owner's Pokémon must be evolved from a Pokémon of the same owner, which also proved to be unpopular, as the element of mixing and matching cards from different sets is lost. Additionally, some of the "Rare" cards had little or no value in play, such as Misty's Tentacool, which is incapable of doing damage and is overshadowed by a better version of "Uncommon" rarity. However, Owner's Pokémon have been sporadically released in Japan, though except for those within EX Team Magma vs Team Aqua, none have been translated into English. This set was originally released with theme decks that contained cards not found in the main set in Japan, releasing in the odd rarities for Basic Pokémon.

This set is also the first set to introduce Stadium cards, trainers that stay in play until another Stadium card comes into play.