Just for fun, have been creating magnetic boxes from terrain data. This one is of Mount Everest. Come with a mountain patterned side version of files and a plain smooth version of files. To get the two tone effect of colors I paused the print and changed the filament half-way through.
Comes with three different types of bottoms. One for games like D&D with an area for dice and other items, another that is split down the middle with a divider for any ranbom things, and one with just plain openness.
Examples printed at 0.2 mm line height and 15% infill. I would recommend not doing less than 15% infill, it prevents warping of the lid so that the tops and bottom fit together good.
Made for 6x3 mm magnets. I got some here for $14: