A bit of a spin on the test cube. This model is 25 x 40 x 10 so a little bigger than a standard test 20 x 20 cube but this can be printed in different orientations to test how well your printer deals with holes and overhangs.
I'm getting into 3D printing so I am printing quite a few test items, I have found giving these to friends, they are liked more than just a cube.
I made the plush one a few years back and has become a bit of a mascot, he is just called Stone man
Print on the best settings you feel. The one in the picture is 0.3 with 30% infill and printed laying down.