The international Pokémon Stadium allowed all 151 original Pokémon species to be used in battles.
Pokémon Stadium was a Nintendo 64 strategy game built around fully rendered 3D battles. Players could select teams from the original Kanto Pokédex or transfer trained Pokémon from Pokémon Red, Blue, and Yellow with the Nintendo 64 Transfer Pak.
The number is easy to confuse because the Japanese predecessor, Pocket Monsters Stadium, had a much smaller selection of 40 Pokémon. That Japan-only title was released in 1998, while the international Pokémon Stadium appeared in Japan in 1999 and later reached other regions.
The game also included four Cups, the Gym Leader Castle, mini-games, and a Laboratory for managing transferred Pokémon. Its 151-species roster covered the complete original Pokédex, although only three selected Pokémon were used at a time in individual Stadium battles.