12. Web Designer’s Icon Set
Free to use commercially - credit required
The set consists of web application icons, user interface icons, e-commerce icons, general use icons, desktop icons, blog icons, smiley icons, button icons, keyboard icons, national flags icons, popular online services icons and many others.
It's another set of icons that have been done for Smashing Magazine - so it is probably worth while checking through their website to see what other icon sets they have.