This is a very cool design I found online for a multi-microSD card holder. The original design is by kozalakisk and the original remix by Kroki. I just added the text "FULL" at the bottom. For the sake of convenience, I included the original remix by Kroki (without any text at the bottom).

More info and 3D printing footage in this video: https://www.youtube.com/watch?v=XWjbD5kkod8

Here is how you can easily modify this (and any other) design in Tinkercad: https://www.youtube.com/watch?v=JZXR5rOJ_QM

This is a remix from: https://www.thingiverse.com/thing:4574249 which is based on this original design: https://www.thingiverse.com/thing:5025071