Daniel Bruce in collaboration with Smashing Magazine offers a free set of universal 284 carefully crafted pictograms for regular design projects. The icons are available as EPS, PDF and Photoshop PSD files as well as desktop typefaces (TrueType, OpenType) and Web fonts.
Pictograms are licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported license. You are free to distribute, transform, fiddle with and build them into your work, even commercially. Though you still have to meet license requirements: give attribution to pictogrms’ author Daniel Bruce and share your work with same licence (CC Attribution-ShareAlike 3.0).