Really Good UX - A library of screenshots for UX inspiration
Laws of UX - Key maxims that designers must consider when building UX
Usability.gov - Resource for user experience (UX) best practices & guides
prodmgmt.world - Quickly find product & UX techniques to get unstuck
UX Check - Easy heuristic evaluations on your website (chrome ext.)
Checklist Design - The best UI and UX practices for production ready design.