Anima App - Design, get feedback, convert to code, publish, iterate.
Sketch Repo - Collection of resources for anyone who uses Sketch
Sketch 101 by Designlab - Learn Sketch in this free course w/ downloadable templates
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
RookieUp Career Bootcamps - Tools to help designers build great portfolios and get jobs.
Git Sketch Plugin - Version control for designers