Tractor which can be printed in PLA, TPU (for the tires) and needs four 608 bearings and some metric nuts and screws (M3x25 for the body and M3x5 oder M3x6 for the wheels).
My 15 months old daughter loves it and it is robust.
Use at your own risk. Small parts can break off.
DasFilament PLA & TPU
Green, Red, Black