One thing I like to use my 3D printer for is improving board games. Especially when it comes to all the tokens and figures and whatnot, we like to use foam core and 3D printed elements to keep things better organized.
This is an insert I made for the kid’s version of Andor (it’s marketed under a few different names depending on the language, here in Germany it’s called “Andor Junior”, Board Game Geek lists it as “Andor: The Family Fantasy Game”).
The insert is the same height as the box (so you can also stand the box upright without everything falling out), and holds all the small tokens and dice.
Board game geek link: Andor: The Family Fantasy Game
Thingiverse link to the 3D files: thing:5337354
I used tinkercad to design this insert (which I use a lot for these kinds of things), for more technical designs I use the free version of Fusion 360.