Here you can find the HTML5 Security Cheatsheet, which is a nice source of some good XSS payloads.
XSS via formaction – requiring user interaction (1)
A vector displaying the HTML5 form and formaction capabilities for form hijacking outside the actual form
Self-including DOM Worker XSS
A self-including code snippet utilizing a DOM worker and firing a message event to itself causing script execution
Self-hijacking JSON literals
In case parts of a JSON literal are controlled by user input there’s a risk to allow auto-harvesting values from later object members.