NASA has a bunch of its 3D models up on GitHub, and if you didn’t know about it before, you do now. It’s a ridiculously large download, at over one and a half jiggabytes, but it’s full of textures and high-resolution models of spacecraft, landing sites, and other random NASA ephemera.
Not all of the models are in formats that we can read — maybe some of you can? — but there are STL files galore in the “3D Printing” folder. These include a printable Curiosity rover, the famous 3D-printed ratchet wrench, and more. That said, this is a collection of random tidbits rather than a complete catalog, so some things that you’d like may just not be there. In other folders, you’ll find textures that’ll be useful if computer modeling is more your thing than printing.
There are also terrain maps of the various Apollo landing sites, so if you want to fake your own 3D-printed moon landing, you’ve now got what it takes.