Adobe XD - Adobe XD is an all-in-one UX/UI solution for designing websites, mobile apps and more.
Sketch Repo - Collection of resources for anyone who uses Sketch
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
AT-UI - UI library for developing powerful web interfaces
Sketch 42 - Now with export presets, touch bar integration, and more
UI Libraries by Shuffle - A marketplace for busy front-end developers