Notable 1st party Gamecube games: Pikmin+Pikmin 2, Donkey Kong's Bongo games (there are 3 I think, and another is coming), Fire Emblem, 2 Zeldas (another one coming, plus a disc that includes Zelda 1, Zelda 2, Ocarina of Time & Majoras Mask), Animal Crossing (Get it for DS. If you don't have a DS get one)

Since you said nothing Mario or Metroid. There are tons of Mario related games-- Mario Parties, Mario Sports games, etc.