Humaaans - Mix-&-match illustrations of humans with a design library.
Anima App - Design, get feedback, convert to code, publish, iterate.
Avataaars - Mix and match avatars with a Sketch library
Sketch Repo - Collection of resources for anyone who uses Sketch
Sketch Icons - Generate a dynamic icon library in less than 5 minutes
Auto-Layout for Sketch - Responsive design for Sketch