Hex Chess Set with 5x1mm magnet pocket added

Embedded magnets, 5x1mm + tolerance. If using Cura at 0.2mm layer height you'd need to pause on layer number 11.

If there's nothing magnetic in the extruder gantry you might get away with not gluing the magnet down but I wouldn't chance it. A small drop of glue should be enough, test with something magnetic that it's actually stuck before unpausing the print, and be careful about the orientation of the magnets of course.

Recommended to have a extra dummy body (just a cylinder or whatever) that gets printed first in order to prime the nozzle again after being paused.