I keep losing my memory cards, so when I had some extra time on a laser machine I decided to do something about it. I had some 2mm cardboard laying around so I designed a pretty simple drawer-like system to protect the cards between a couple of cardboard sheets.  

The whole layout is really small, you can actually cut two holders from a single A4 sheet. You can also personalize it by engraving your own designs. 
Feel free to download the ready-to-cut files here.