Designed and printed a holder for T-handle hex wrenches:
hexkeystand.stl (127.0 KB)
which worked well when I printed it:
EDIT: Improved STL which replaces the hexes w/ 12 pointed stars, so it should work for any sort of hex key:
hexkeystand.stl (118.3 KB)
Size should match the other 3D print library files.