Just got an Ender 3, and for now moving files via micro SD card. These are really little... great for data,, less great to handle frequently. I just slide this 'handle' onto the micro sd card, and it is a bit more manageable. The gap and size of these cards are all pushing limits of resolution of these plotters,, but my cards fit snug with no adhesive required.

Yes,, i am going repeat with a bright color so I can also find them :). or add holes for key ring or...

I added an updated holder. it works better and is much stronger. I have found that printing is weaker between layers, so printing this one on its side. will likely need some clean up after print, but so far works better.