Website: GRABCAD

• Variety of functional & technical models.

Website: MY MINI FACTORY

• Paid and free models, guaranteed to print. Contains a collection called Scan the World, which features scans of artifacts from museums worldwide.

Website: PINSHAPE

• Free and paid models.

Website: PRINTABLES

• Variety of models, some free and some paid, for different purposes, from personal projects to home decoration. Note that it's recommended to check gcode files by running it through a checker such as Gcode Checker

Website: REDPAH

• Free and paid models.

Website: THANGS

• 'Community for makers, hobbyists, designers' - Offers a library of 3D models.

Website: THINGIVERSE

• The world's largest 3D model hosting service.

Website: YOUMAGINE

• 'Where creators and innovators share and inspire' - contains opensource models.

Website: NIH PRINT EXCHANGE

• Scientific and medical models curated by the US National Institutes of Health.

Website: SMITHSONIAN DIGITIZATION

• A collection of scanned models from the Smithsonian Museum's collection.