User Inyerface - A painful illustration of bad UX
Interfacer - Collection of more than 200+ free design resources
Befront - Learn UX/UI design skills in practice with bite-sized tasks
Designer Mill - Collection of Best Free Design Resources
Frontend Mentor - Supercharge your front-end skills by building in a real-life workflow. Solve real-world HTML, CSS and JavaScript challenges whilst working to professional quality designs.
Product Disrupt - A design student's list of resources to learn Product Design