Checklist Design - The best UI and UX practices for production ready design.
UXsniff - Track user behavior on your website and improve conversions with UXsniff: the user experience watchdog that looks out for you.
Rage Grade by FullStory - Benchmark your customer frustration
Uxcel - The easiest way to learn UX/UI design
Toole - Search for and discover online tools
uEye - uEye is free, fun, and an interactive way to learn UI design.