It would be one of either the Large Body, the Flantastic Seven, or the Darkling for me. The Darkling seems to be like what happens to a Keyblade wielder. The Flantastic Seven Heartless seems like a cool and fun kind of species with how their mini games are. The Large Body is a round brawler who seems to use its own round body in comical ways.
If we’re including bosses, I’d say Phantom, otherwise it’d be Invisible. Both can fly and have badass designs.
What’s your favorite thing about both?
Other than the fact that 7 year old me couldn’t beat either of them for the life of me?
Honestly I thought phantom had the coolest mechanics as a kid, and would quite literally be invincible to anyone who wasn’t an expert magic user. And really, Invisibles just feel like cooler, stronger, sword-wielding neoshadows. They got a super cool aesthetic going on.