This is a full height bracket for MHGH28-XTC cards, for 3D printing. (this 1-5 version is a bit better fit than the previous 1-2 version)
Seems ok (so far) when printed at 0.1mm with ABS. Fits in my mid-tower ATX cases well.
There's a low profile version of the card here, if that's useful too: MHGH-28XTC-low_profile_bracket1-7.stl