We were after some magnetic hooks to hang some tea towels from.
All the ones I found were just the wrong size for the neodymium magnets that we had.
So I designed this quickly in OnShape.
I printed it in Creality PLA CF (because that was what was in the printer at the time :-) )
I did 35% infill, and I am quite happy with the strength of them.
The only thing I ended up doing was making between the slot and the back of the hook quite thin so that the maximum amount of magnetic force was holding the hook up.
The hook can take up to three 12mm by 3mm magnets.
If you print it in with the slot for the magnets facing up there is no need for any supports. there is the maximum amount of strength, when printed this way, on the actual hook due to the direction of the layers
The original file is here https://cad.onshape.com/documents/dd6d5f6e8df8e4c789ec16f8/w/080a5ae74925e9bd370fd010/e/b5c3123836149a8bb7cce874?renderMode=0&uiState=64d5d2a3daeda16b44c3320b for if you would like to modify it
The author marked this model as their own original creation.