HTML5 made easy with HTML5 Cheat Sheets is an interesting blog from Alice Pang. I really like the idea from InMotion Hosting to create cheat sheets on HTML5 Tags and HTML5 Event Handler Attributes. The cheat sheets may need to update from time to time but these are good enough as a starting point. Note, it’s Browser Support cheat sheet is very out of date so I won’t really use it.
HTML5 Tags (New, Existing, and Unsupported)
HTML5 Event Handler Attributes (New, Existing and Unsupported)