The true value in a 3D printer lies in its ability to prototype a something that you cannot readily buy, something that only exists in your head.
Printing out random doodads from Thingiverse is not only wasteful but unfulfilling. You might as well go raid the dollar store toy aisle.
I would recommend spending some time and learning how to use a CAD software. Fusion360 is a popular choice, although with a bit of a learning curve. TinkerCAD is a good browser based option as well, excellent starting point for beginners.