PokeMMO

PokeMMO is a fan-made, free-to-play MMORPG that merges several classic Pokémon regions (Kanto, Hoenn, Sinnoh, Unova and Johto) into one shared persistent online world. Trainers explore, trade on a player-driven economy, and battle each other in PvP. It is unofficial and not produced by Nintendo or The Pokémon Company.