Prototypo - Streamlining font creation with open source typeface editor
Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
BitFontMaker2™ - Fast and easy Online Bitmap font Editor.
Smartmockups - Create stunning product mockups, easily and online.
FontForge - Free (libre) font editor for Windows, Mac OS X and GNU+Linux
MockMagic - A free, easy-to-use device mockup generator