This is an insert that allows you to store a Magic The Gathering Mini Deck in a standard sized Deck Box, along with dice, counters and just for giggles a jewellers loupe.  
 

In the photographs, you will see this insert coupled with @iansmithbuilds excellent deck box ([https://www.printables.com/model/588750-mtg-card-deck-box](https://www.printables.com/model/588750-mtg-card-deck-box))

Checked with a judge and the mini deck is allowed in tournaments.  

Now where can I find some Commanders that are 4 x larger than a standard game card?

(Cat not included - she is called Evie)