Steam has a selection of mac games, including "Steam Play" (where you can purchase the game and it will work on multiple OS like linux, OS10, and Windows). GOG.com also has Mac ports (like Master of Orion and Brutal Legend)
Lots of Blizzard Games are available on Mac. Sims and Simcity are also available.
Finally, Feral Interactive ports a lot of games from Windows to Mac.