Another good starting point is (the late, great) Gamba's site: home.earthlink.net/~gamba2. There's a large list of links to other sites from which you may download until your hard disk explodes. Many of the links may no longer be valid, but lots of them still work.

There's also the (French) Mac attic: http://www.grenier-du-mac.net/index.htm

Lots of games, and some apps there.

I'm sure others here will chime in shortly with their faves.