Fixkeys - Description and fix of problems with keys like backspace and home in console, X, terminal emulators, editors and applications. - http://x.mame.net/hans/fixkeys.html
WMKeyboard - A WindowMaker dockapp that allows users create and apply keyboard maps. It also acts as a switch between two keyboard maps of choice. - http://wmkbd.sourceforge.net/
XKeyCaps - A graphical front-end to xmodmap. It opens a window that looks like a keyboard; moving the mouse over a key shows what KeySyms and Modifier bits that key generates. Clicking on a key simulates KeyPress/KeyRelease events on the window of choice. - http://www.jwz.org/xkeycaps/