Loved the simple Pi Keychain by LINUX, though wanted to create a version with a larger round hole to accommodate a standard keyring. Downloaded the original .stl file and edited it using Tinkercad. The finished size is 22 mm x 27 mm. No raft or supports needed.
We also turned some into earrings with standard earring fittings. Earring photo shows placement next to a quarter for scale.
It takes about 50 minutes to print 9 of these at once using these settings.