Git Sketch Plugin - Version control for designers
Anima App - Design, get feedback, convert to code, publish, iterate.
Fluid for Sketch - Sketch plugin to make your responsive designs more efficient
Sketch Repo - Collection of resources for anyone who uses Sketch
Sketch Plugin Course by Design+Code - Enhance your design workflow by creating a Sketch plugin
Adobe XD - Adobe XD is an all-in-one UX/UI solution for designing websites, mobile apps and more.