Select Similar Layers - Sketch plugin to select layers with the same attributes
PSD to Sketch Design Converter - Convert a Photoshop design to a layered Sketch file for free
Framer Inventory 3 for Sketch - Import states & export prototypes from Sketch to Framer
Zeplin - Collaboration app for UI designers & frontend developers
UXpin - Design is really about solving problems. UXPin is the UX Design Platform that gets that right.
Sketch Repo - Collection of resources for anyone who uses Sketch