Git Sketch Plugin - Version control for designers
Fluid for Sketch - Sketch plugin to make your responsive designs more efficient
Marvel Sketch Plugin - Rapid mobile and web prototyping with Sketch
Unsplasher - Fill shapes or symbols in Sketch with images from Unsplash 🖼
Connection Flow Arrows - Create connected arrows for sitemaps & user flows in Sketch
Design Systems Repo - A collection of design system examples and resources