I have whiteboards and work which are metal backed. I also had a few magnets to hold paper on the boards with holders to allow me to move them easily. Asked in the office if we had any more - nope. I had a few HDD sitting around needed to be dismantled, so I went to town.
I collected a couple of these Neodymium magnets (broken in half) and designed this simple and elegant holder for them.
Take note, it is designed for HDD magnets, broken in half. If you have a full size magnet it will stick out.
This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/5EJjStcMHxE
Anet A8 stock settings. Used Cura 3.1.0
Wall thickness 0.8
Top bottom 1.2
First layer 0.3
bed 60% hotend 200 PLA