Git Sketch Plugin - Version control for designers
InVision Studio - The world’s most powerful screen design tool
Anima App - Design, get feedback, convert to code, publish, iterate.
Craft by InVision - Sketch and PS plugins to pull live data into your designs
Marvel for Sketch - Sync, play and record prototypes in Sketch!
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.