This is an alternate insert to D&D - Dungeon Mayhem - Monster Madness expansion.

This insert uses the original cardboard dividers and allows them to be tilted forwards and backwards towards the slanted ends, just like with the original insert. The sides are 6 mm thick, so the dividers stay put and don't scrape the sides of the box too much. There is enough room for cards with Sleeve Kings Standard USA Chimera Card Sleeves, or other sleeves that are upto about 3 mm longer and somewhat wider. The space available for a single character deck is 15 mm, which is more than enough for the 60 micron Sleeve Kings.

The token box fits into the front of the insert. The insert itself is 224 mm long, which fits nicely into the box. There is enough room on the side of the box for two more future 2 deck expansions (like the Battle for Baldur's Gate, if WoTC ever releases more).

I have also created Dungeon Mayhem Token Holders that fit into my
Dungeon Mayhem Stackable Token Holder Rack that fits into the token box slot.

Anycubic 4max Pro

No

No

0.2

10%

The print took 12.5 h and used 109 g of filament, but the result is good enough for me.
If you want a faster and cheaper build, feel free to edit.
The MonsterMadness-slim-experimental.stl is a quick and untested version with slimmer angled walls that takes 11 h and 91 g with the same settings.