This is a thread i can get into!
I should have more ideas as i move to the interior work on my 4R and hopefully can regain access to the printer at my office.
A while back i was able to design and print a few bits for my other cars.
for my bugaru i made an oil cap(from the factory it had a long filler neck that didn't fit under the vw decklid.
and an ebrake cable spacer to tighten up the stretched out factory cables.
My e39 has terrible factory cupholders so i built one for it. Can't find the files but i'll take a pic later.
Edit:
Also made my wife a keychain for her Pro4
and a bottle holder for my swell bottle so i could hook it onto a backpack while hiking
I think my first step might be a bezel for my inclinometer