KeyCue - Menu shortcuts are supposed to provide quick access to frequently used menu commands.
CopyPaste.me - Frictionless sharing between devices
CheatKeys - View Windows keyboard shortcuts in the current application.
SmartPaste - Copy-paste nicely styled text to apps like GMail and Google Docs without learning new shortcuts.
cheat - Cheat allows you to create and view interactive cheatsheets on the command-line.
Keyviz - Visualize your keystrokes in real-time