Shapefest - A massive library of 3D shapes for everything!
Wannathis - 3d illustrations and freebies
Khagwal 3D Illustration Library - Free 3D illustration library for web & mobile app designers
Iconscout - Design Resource Marketplace.
ccclaymoji - A fun little tool to make emojis that have a fun 3D-like effect.
Craftwork - A collection of User Interface resources made by Craftwork