Calle's Custom Icons
Icons of flags, folders, and more. Also provides information about the designer and a list of frequently asked questions.
Feòrag's Free Stuff
Download free fonts, icons and desktop patterns for the Macintosh.
Mike's OS X Icon Design
Icon design and consulting, custom Mac OS X photo-illustrative icons for software developers applications.
Squid Action
Desktop pictures, and icons for Macintosh OS X, with illustrations, and photography by Pat Beyer.
The Cop Shop
A set of icons and several desktop wallpapers featuring images of Victoria (Australia) police vehicles.
The Iconfactory
Developer, of freeware icons for the Macintosh and home of the 'Pixelaplooza' contest, an annual forum for all icon artists. Links to other interconnected icons sites.
Xicons.com
Wide variety of new icon sets for Mac OS X. Also offers how-to articles about creating icons and icon creation contests.