Womp - 3D Made Easy
Icons8 - Free app for Mac & Windows already containing 39,800 icons. Allows to search and import icons…
365+ 3D Printing Objects - A year's worth of monetizable 3D printing things.
Iconscout - Design Resource Marketplace.
AstroPrint - Slice, Store, and Print your 3D files from any web enabled device.
Craftwork - A collection of User Interface resources made by Craftwork