Which console was used for Pokémon Stadium, the 1999 3D Pokémon battle game?

Pokémon Stadium was released for the Nintendo 64.

The 1999 game brought Pokémon battles into a 3D arena, using the Nintendo 64’s hardware to display animated models of the original 151 species. Nintendo EAD developed and published the game.

Pokémon Stadium connected to Pokémon Red, Blue, and Yellow through the Transfer Pak accessory. Players could use compatible Pokémon from their Game Boy cartridges in battles, view and organize them, and access other features. The game also included four Cups, a Gym Leader Castle, and mini-games.

The Japanese release came in 1999, followed by North American and European releases in 2000. It is often confused with Pocket Monsters Stadium, an earlier Japan-only Nintendo 64 game from 1998 that supported only 40 Pokémon. The international Pokémon Stadium expanded the playable roster to all 151 original species.