FontForge Portable is an outline font editor that lets you create your own postscript, truetype, opentype, cid-keyed, multi-master, cff, svg and bitmap (bdf, FON, NFNT) fonts, or edit existing ones. Also lets you convert one format to another. FontForge's file selection box is a bit unusual. You can switch between drives using the bookmarks menu. Be sure not to remove any drive bookmarks as you would be unable to switch between drives as you move PCs.