Device Shots - Generate high-resolution device mockups using a screenshot.
Select Similar Layers - Sketch plugin to select layers with the same attributes
shotsnapp - Create beautiful device mockup presentation
Framer Inventory 3 for Sketch - Import states & export prototypes from Sketch to Framer
Base UI Sketch Framework - Huge set of everything you need to design and prototype
UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.