Open Icon Library. Free and Open to use and modify as needed. Over 10,000 icons in svg, png, xpm, ico, and icns formats. All icons are under free/open licenses, however the licenses vary from image to image. Some are Creative Commons, some are GPL, some are Public Domain. Licenses for sources app-install, wiki_commons-BSD, wiki_commons-CC, wiki_commons-GPL, , wiki_commons-MIT, and wiki_commons-PD