This ExpressCard Caddy lets you store things in your notebooks ExpressCars slot. In total there are seven different versions.
If you have any improvement suggestions feel encouraged to send me a message.

[EDIT 12.02.2016]
A lot of testing with various ExpressCard Slots showed that some of the adapters could cause a few problems (none of them damaging the slot, though. At least if you're not trying to mount the adapters with a hammer).
A great overhaul is in the making and even more testing is planned. Expect an update in a few days.
[/EDIT]

54 mm variants:

• 2x SD-card + 2x microSD-card
• 1x Logitech Unifying receiver + 1x SD-card + 2x microSD-card
• 1x USB stick + 1x SD-card + 2x microSD-card

34mm variants:

• 1x SD-card + 2x microSD-card
• 1x Logitech Unifying receiver + 2x microSD-card
• 1x Logitech Unifying receiver + 1x SD-card
• 1x USB stick + 2x microSD-card

So far the 34 mm versions and the USB Slot are not properly tested. The 34 mm caddy works in a 54 mm slot. Since the only difference are 20 mm of space at the side of the slot I am positive that it'll work nonetheless. The USB-slot has the same cross section as an USB A plug and a length of 45 mm. Sticks that don't widen after the metal casing of the plug itself will fit just fine.
Testing is in the works.

The idea was inspired by thing #145073 (by jtopinskis) but is no remix
https://www.thingiverse.com/thing:145073