Free Audio Units By Blue Cat

http://www.bluecataudio.com/Products/Bundle_FreewarePack/

The bundle contains a wide range of modulation effects as well as analysis tools to get you started with your DAW, for free!
NEW: Mac support. Our free plugins now include Mac support. The Mac version of our free plugins require Mac OS X Leopard (10.5) and a VST-compatible or Audio Unit application (Audio Units version is beta 2).

Here is the direct download links to spare you going to their page:
Download: Mac AU (beta) / Mac VST / Windows DX / Windows VST

Edit:
I couldn't get the Beta AUs to work in Logic?