Anywho, back on topic.
GB and GBC are the same dimensions. GBA has same main width, but with added the 2 pegs at each side. Are there any crazy style GB, GBC, or GBA carts out there?
Other than those already mentioned...
Kirby's Tilt'n'Tumble's cart is slightly different from standard GBC carts. It's dimensions are mostly the same but it's
slightly thicker at the top.
Drill Dozer is another GBA game with a unique cart shape. Its dimensions are similar to Yoshi Topsy Turvy, but not exactly the same.
Pokemon-clone "RoboPon" had
a weird tall cartridge with an IR port built in.Gameboy Camera, obviously

And various models of Gameshark/Action Replay/etc.
That's all I can think of.