D20 Holder
thingiverse
I've been using a quality dice holder while playing Magic the Gathering and it's really worked out well for me.
Download Model from thingiverse
With this file you will be able to print D20 Holder with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on D20 Holder.