FontForge - Free (libre) font editor for Windows, Mac OS X and GNU+Linux
Sketch - Professional digital design for Mac.
Glyphs - Make everything from dingbat webfonts to full-fledged text typefaces in the most Mac-like font...
Inkscape - Inkscape is a free, open source professional vector graphics editor for Windows, Mac OS X and Linux.
FontCreator - This professional font editor allows you to create and edit TrueType and OpenType fonts.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.