Shared Text Styles - Easily import and export your Text Styles in Sketch.
Flowkit - Sketch library for user flows/content maps/annotations
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.
Framer Inventory 3 for Sketch - Import states & export prototypes from Sketch to Framer
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.
Rawson Framework - Create amazing Sketch apps for iOS