Isometrica - 3D illustration constructor with 380+ isometric objects
Open Peeps - A hand-drawn illustration library.
Characterz - Biggest diverse mix and match 3D illustration library
Open Doodles - A collection of free sketchy illustrations
Khagwal 3D Illustration Library - Free 3D illustration library for web & mobile app designers
Sargam Icons - 700+ open-source icons for your exquisite designs.