I recently found all my MTG card that I used to play with 20 years ago.
They were inside a big messy tin box. So I came up with this cheap and quick solution to store them in a more organised way.

Recycling a cardboard filament box, I designed card holders that can easily fit inside it.
The divider part is then used to fill the remaining gap in the box.

I printed everything in PETG, cause this material have better layer adhesion than PLA.

To clean the card holders, I used a deburring tool and an exacto knife.
The picture below shows the difference from before and after the cleaning process.

The card holders can also fit Pokemon cards and every standard size playing card without sleeves in general (2.5 x 3.5 inches - 6.35 x 8.89 cm).

I quite like the recycling intent of this solution.