KeyCue - Menu shortcuts are supposed to provide quick access to frequently used menu commands.
CodePen - A front end web development playground.
CheatKeys - View Windows keyboard shortcuts in the current application.
JSFiddle - Test your JavaScript, CSS, HTML or CoffeeScript online with JSFiddle code editor.
cheat - Cheat allows you to create and view interactive cheatsheets on the command-line.
Liveweave - Liveweave is a HTML5, CSS3 & JavaScript playground for web designers and developers