Control Illustrations - 108 free flat illustrations with customizable characters
Isometrica - 3D illustration constructor with 380+ isometric objects
Humaaans - Mix-&-match illustrations of humans with a design library.
Characterz - Biggest diverse mix and match 3D illustration library
Open Peeps - A hand-drawn illustration library.
Khagwal 3D Illustration Library - Free 3D illustration library for web & mobile app designers