Anima App - Design, get feedback, convert to code, publish, iterate.
Sketch Repo - Collection of resources for anyone who uses Sketch
Gmail Add-on Design Kit - A simple Sketch library to speed up Gmail Add-on designs
Git Sketch Plugin - Version control for designers
Charts by ls.graphics - The most comprehensive collection of charts for Sketch
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.