An aggregator that indexes various free avatar sources that you can use in your design mockups by copy—paste, API and Sketch plugin.
Create robot illustrations in Sketch App with this free library. Combine frames, antennas, sensors, accessories, and colors.
Pictogrify is an open source library that allows you to generate a unique pictogram from a given text.
Diverse UI is a free collection of diverse user-submitted images that can be used in your design work.
Tiny Faces is a free crowd-sourced avatar gallery to use in your personal or commercial projects.