Pokémon Mystery Dungeon Series (GBA/Nintendo DS): There have been several Dungeon games since the release of the originals in 2006. The series puts you in the shoes (or lack-thereof) of a Pokémon in a world entirely populated by the creatures. Your mission is to figure out why you are no longer a human, saving your fellow (Poke) men from dangerous “dungeons.” The storyline of each entry never disappoints and is diverse enough from game to game to try them all.
PokePark: Pikachu's Adventure (Wii): Pokepark features a 3D world of Poke-wonder where you, as a Pikachu, visit different attractions, play mini-games and aim to meet Mew. The graphics are a definite improvement over the DS games, showcasing how amazing a main series release would look on a Wii (nowadays, on a Wii U).
Pokémon Ranger Series (DS): In the Ranger games, you act as a park ranger in the Pokémon world. You don’t battle pocket monsters like the main series game; you protect them. The series’ focus on protecting the environment and the creatures in it is refreshing.
Pokémon Snap (Nintendo 64): Taking photos of Pokémon doesn’t sound fun, but Snap made it the pastime of kids everywhere. I’m genuinely surprised this hasn’t received a remake yet.
Honorable Mention: While I have never personally played these games, I know they are spoken highly of by Pokefans: Pokémon Colosseum and
Pokémon XD: Gale of Darkness. They are on my “need to play at some point” list. Pokémon Art Academy (3DS), which teaches you how to draw Pokémon, is another game I’d like to try.
Games I have played that are also worth a shot are puzzle-themed Pokémon Trozei (DS) and Pokémon Pinball (Gameboy Color).