shotsnapp - Create beautiful device mockup presentation
Sketch Repo - Collection of resources for anyone who uses Sketch
Base UI Sketch Framework - Huge set of everything you need to design and prototype
Anima App - Design, get feedback, convert to code, publish, iterate.
Sketchapp TV - Create Awesome iOS Apps With Sketch
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.