Gym Heroes and Gym Challenge completed sets : r pkmntcgcollections 2000 Pokemon Gym Challenge Gaming Gallery Trading Card Database PokeDATA Up to date Gym Heroes (Pokemon) card list! MARKET UPDATE: Gym Challenge (Top 15 Most Expensive Cards) This set is considered as the final expansion of the OG Kanto focused series, also, It's harder to complete than Jungle or Fossil because Gym Heroes was released in August of 2000 and was the 6th Pokemon Set printed by Wizards of the Coast! Shortly after we got the Gym Challenge set and collectors confused the two ever since !