Pikmin 1 and 2
Once again Nintendo crafted a game series like nothing else when they created Pikmin. You play as Olimar, an astronaut who’s crash-landed on an alien planet and encounters little creatures called Pikmin. Different colored Pikmin have different uses, and you have to command the creatures to solve puzzles and battle enemies.
Baten Kaitos: Eternal Wings and the Lost Ocean
Baten Kaitos is an RPG developed by Monolith Soft, the same team behind the Xenosaga series and Xenoblade Chronicles. The game tells the story of a young man named Kalas and his companion Xelha, who live on a floating continent. It had an interesting card-based battle system and absolutely unforgettable soundtrack.
Final Fantasy Crystal Chronicles
Square Enix created a successful spinoff series with Crystal Chronicles on the GameCube, a title that created a brand new world and set of races. The game still retained many of the traditions of Final Fantasy like magic and a job system, but featured real-time combat with a tactical flair.
Chibi-Robo!
Chibi-Robo has become another mascot character for Nintendo, although he is a little less popular than the big names like Link and Mario. The first title in the series on GameCube had you take control of the adorable little robot as he navigates around a household collecting “Happy Points.” It had a charming storyline and unique gameplay mechanics, like having to recharge by connecting to outlets.
Pokemon Colosseum
Pokemon Colosseum is about the closest we’ve gotten to having a mainline title on a home console. The game takes place in the desert region of Orre and has you playing as Wes, a former member of Team Snagem. You don’t capture Pokemon in random battles, but instead “snag” the Pokemon of other trainers. It had a fun original storyline, and most battles were fought in the “double” format.