Prusa Printers – 3D Model Database
https://www.prusaprinters.org/prints

Thingiverse – 3D Model Database
https://thingiverse.com/

3D Model Database – a search engine for 3d models
https://3dmdb.com/

Tinkercad is a free, easy-to-use web app that equips the next generation of designers and engineers with the foundational skills for innovation:
https://tinkercad.com/