Base UI Sketch Framework - Huge set of everything you need to design and prototype
Sketch 42 - Now with export presets, touch bar integration, and more
SketchCasts - A weekly screencast, all about how to use Sketch
Anima App - Design, get feedback, convert to code, publish, iterate.
Remake - A way to make web apps with just HTML & CSS
Sketch Repo - Collection of resources for anyone who uses Sketch