There used to be some indie Mac (and later iOS) only game studios like Pangea Software (makers of Nanosaur, Bugdom, Otto-Matic, and Enigmo among others) but I'm

There used to be some indie Mac (and later iOS) only game studios like Pangea Software (makers of Nanosaur, Bugdom, Otto-Matic, and Enigmo among others) but I'm not sure how many of those are still around. As far as bigger studios go, Bungie was a Mac studio until Microsoft scooped them up to turn Halo Xbox-exclusive instead.