Pokemon Trading Card Game 2 (Game Boy Color)
Pokemon Card GB2: GR-dan Sanjo! (Pokemon TCG2) is the continuation of the Trading Card Game that came out for the Game Boy alongside the first generation of Pokemon. This game was only ever released in Japan, and this version is a fan-made translation (homebrew/fanmod).
It features many improvements over the first game, especially the story (focused on Team Great Rocket) and a roster of 445 cards. It never left Japan because many of those cards never existed in the Pokemon TCG in Western languages.
Thanks to a translator hero, you can now enjoy this game that never officially made it out of Japan. The game is playable in English, German or Spanish.