FontForge - Free (libre) font editor for Windows, Mac OS X and GNU+Linux
Octicons - Your project. GitHub's icons.
Glyphs - Make everything from dingbat webfonts to full-fledged text typefaces in the most Mac-like font...
Themify Icons - A complete set of icons for use in web design and apps, consisting of 320+ pixel-perfect, hand-crafted icons that draw inspiration from Apple iOS 7.
BirdFont - Birdfont is a free font editor which lets you create vector graphics and export TTF, OTF, EOT and...
WebHostingHub Glyphs - High quality icons that are easy to use with Bootstrap, other CSS frameworks and in any web projects.