It seems that most of the drywall mounts that I looked for printed in a vertical orientation, which is not good for strength.
For once, I didn’t reverse engineer anything to design this. Lulz.
https://www.printables.com/model/548516-printable-drywall-mount
Update 8/10 - Added dimension sketches, Added .step file, Added a thinner support ring option that will sit more flush (but not completely)
They sit 3mm proud. This is not an issue if they are hidden, me thinks. However, you should be able to not use the support ring if it is an issue. (I’ll modify a design today in attempt to reduce the amount it sticks out.)
Also, these are intended to be extremely secure and almost permanent. If you want it flush, you can probably pound it in a little more with a hammer. If not, leave it proud and it gives you a little meat to pull it out of the wall later.
Cool. Appreciate the effort!
I added another version today that has a 2mm ring without the chamfer, btw.