A very simple bookend - printing as I type this (ABS).
I tend to print with objets at -0.07 (z) to prevent the need for a raft - so far has worked well. I'm using helper discs on the corners of this to prevent warping since it's a thin flat section prone to such.

Trying with low settings (0.3mm height, 80mm/s speed, 10% infill with 3 shells).

Update - printed out now, and working good - see pictures. I did sand down the sharp corners... perhaps a mod could be to fillet the corners off.