This box is meant to hold 60 sleeved MTG cards (give or take a few). I also included holes on the sides of the container for magnets (total of 4, 1.66mm thick, 11.95mm diameter) that can be press fit.
https://www.amazon.com/dp/B07GX7Z4DF/ref=cm_sw_r_apan_glt_i_76C6KBDT2KZJ24RTG00T?_encoding=UTF8&th=1