I have a cheap Creality Ender Pro V2. I mostly model and print project boxes for electronics, the oddball replacement part, things to make it seem worth the cost for my wife, and mostly parts for the printer itself.
First few things I printed, to test stuff like flats, things that need supports, etc.
An arm and container for an ESP32 cam that I can remotely turn on, it shows what is is printing, and if I see it is messed up I can stop the print.
This is indicative of most of what I model and print (this is a lithium battery charger board):
I model all sorts of variants, and post them to thingiverse.
It is more to help me have usable electronics that I build, but also getting into modeling and writing stuff in openscad (the so called customizer...) to do things programmatically and not manually create all variations (like I made a small speaker box that you can select the speaker size and some options and it creates the stl files to slice and print.