Back in the days of the Wii, Nintendo, Game Freak, and Pokemon Co. released three Pokemon Mystery Dungeon titles on WiiWare. Those titles were Japan exclusive, but now that changes thanks to the hard work of a group of fans.
Pokémon Mystery Dungeon: Tempest Adventure Squad, Radiant Adventure Squad, and Wildfire Adventure Squad have all gotten English fan translations, and each version has different Pokemon. The games have a focus on the actual dungeon crawling, and don't present much story along the way. With WiiWare's file size limit being 40 MB, developers had to make cuts where they could!