This is a self-designed dice case I made in Fusion 360. The magnets are 10 x 3mm and I glue them in place with Gorilla Gel. This holds 3 full (7-die) sets with space for mini storage & small rolling area. The pencil that fits in this case is a Uni Kuru Toga Roulette https://smile.amazon.com/gp/product/B004OHNTVC/
A bic mechanical pencil will also fit if it is missing part of the clip.
The pictures are from an older version, the new version uses 10 magnets total and has posts to prevent the case from sliding apart.
Hatchbox PLA + Wood
I recommend printing this in PETG for durability. I will also be releasing several versions of this with various designs set into the outside of this case.
No additional work required, but on my wood fill case I spent about 10 hours sanding and then stained with Minwax Red Oak (2 long coats) and semi-gloss varnish.