Eyequant - We’ve built an artificial intelligence that instantly predicts how users will see your website so that you can create landing pages that sell
Really Good UX - A library of screenshots for UX inspiration
Attention Insight - Maximize advertising campaign results and design performance with pre-launch analytics.
Usability.gov - Resource for user experience (UX) best practices & guides
Heurix.io - Heurix is a free heuristic evaluation tool that helps you work out how to improve your website.
UX Check - Easy heuristic evaluations on your website (chrome ext.)