Thingiverse
Thingiverse.com is the place to share digital designs for fabricating real, physical objects.
21 Alternatives To Thingiverse
Cults 3D
Cults is a marketplace that connects designers and people who want to 3D print some objects.
SketchUp 3D Warehouse
The place to share and download SketchUp 3D models for architecture, design, construction, and fun.
Wikifactory
Your all-in-one workspace for collaborative product development. Agile PLM tools for distributed teams. i.e. compare PLM tools, compare BOM tool, compare product development tools
Youmagine
The best open source print files and designs available for you to build upon or simply download and 3D print!
wikiHow
wikiHow is a wiki based collaboration to build the world’s largest, highest quality how to manual.