What are some alternatives?
When comparing Open Peeps and Avataaars, you can also consider the following products
Humaaans - Mix-&-match illustrations of humans with a design library.
Blush - Illustrations for everyone
UI Faces - Avatars for design mockups
Free illustrations - Find free to use illustrations & vectors
Avataaars Generator - A simple avatar generator
Control Illustrations - 108 free flat illustrations with customizable characters