Crystal: Sketch Mirror for Android - Crystal: Sketch Mirror for Android is an application that is designed for viewing your sketch designs in real-time, navigate prototypes and download content related to the sketches for offline viewing.
SketchTool - Export pages & slices out of .sketch docs using CLI
Flowkit - Sketch library for user flows/content maps/annotations
Select Similar Layers - Sketch plugin to select layers with the same attributes
Figma Mirror - Figma Mirror is an application that covers top trending designing or sketching ideas making your teamwork in a single environment and design better products from start to finish.
Base UI Sketch Framework - Huge set of everything you need to design and prototype