I just dropped this on Printables: A FreeCAD based custom size box generator. I’ve been using it for all kinds of stuff. Maybe some of you lot will get some use out of it, too.

https://www.printables.com/model/770701-parametric-simple-custom-box-maker-freecad-generat

Plug in your parameters, make a box with filament hinges – No hardware required. No screws, no nuts, no supports, no glue, no Fusion, no proprietary software, no going cross-eyed looking at OpenSCAD code.

(And yes, the default size in the file will make an M:tG card deck case.)