Classy icons crafted according to Microsoft guidelines. Available in PNG and SVG. Free for a link
Prodigy - Radically efficient machine teaching
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IconStore - Free icon packs by first-class designers
Insanity - All development on this project has been discontinued. If anybody wishes to continue development where I left off, the latest source code snapshot is available in the Git repository . The developer...
Flat Icons - 20,000 unique, customizable icons with free lifetime updates