I've designed a 3D-printable monster truck. Almost 100% printable. I haven't designed printable tires because they are so big that it would cost a fotune in elastomer, and good tires are cheap. I wanted a monster truck that looks like a proper monster truck, and not a truggy with bigger wheels.
https://youtu.be/_6eOmHweF8k
https://youtu.be/VDS8F1Fntyc
Download for free here:
https://www.thingiverse.com/thing:2299884