This is a deck box I designed to fit EDH decks into my zip up card case. The box shape is based on Kvermette's box here: https://www.thingiverse.com/thing:2640555

Boxes are retained shut by 4 small detents; the detents are enough to hold a filled box upside-down without it opening. The boxes are just large enough to hold 100 single sleeved cards and a few tokens. I find the total number of cards highly depends on the brand of sleeves used.