I got bored one day at work and designed this on my iPad. It's just a simple eight sided box and lid designed to hold a full set of seven dice. The dimensions for each dice hole with lid is 1" by 1" by 0.875" (7/8ths) tall. If your dice size fits within those dimensions, you should be fine.

No supports are needed. You can print this in just about any filament type you like, even TPU if you're feeling a bit weird.

Wall thickness, infill, and line layer are really just personal preference. In version three, shown in the pictures, I used half circles as tabs, but they kept snapping off. So I changed them in version four to be quarter moons.

As nearly all other projects I make that use magnets, these use eight 6x3mm magnets. They're cheap and easy to find just about anywhere online. I do recommend using a light touch of superglue. These 6mm diameter magnets are just a hair smaller than the 0.25" holes they're supposed to sit in. Here's the Amazon link where I get my magnets:

https://a.co/d/0jlfGWgU

I also included a 6x3mm Magnet Polarity Checker. You do not have to print this if you don't believe you need it. I personally like to keep one or two around because I use these magnets a lot.