With a lot of the things on Thingiverse, like small storage boxes, it's faster to go to Goodwill. Business card holders though -- I had looked for one forever, then when I got the printer I printed one. Probably the most useful thing so far.
Mostly what I printed before the PLA in the machine absorbed moisture and lost all it's cohesion, was archtiectural models, created in Blender.
The only picture I have uploaded. Five of these make an hemisphere.