Summary

There is a provision for magnets, specifically "4 X 1.5 mm - Mini Round Neodymium Magnets." However, they can be printed as is and then either glue Velcro or magnetic disks to the back, depending on the surface you will be using. These could also make for fun decorations.

I used a technique by printing them with 0 top and bottom layers and a 50% zigzag infill. This saved a lot of time in printing and filament.