Humaaans - Mix-&-match illustrations of humans with a design library.
Avataaars Generator - A simple avatar generator
Avataaars - Mix and match avatars with a Sketch library
AVATARZ - Lovely library of diverse 3D avatars
Sketch Icons - Generate a dynamic icon library in less than 5 minutes
100 Free Userpics - Collection of a hundred free userpics especially for your design projects.