Inspired by a wooden version, created by the "Eigenbaukombinat" Makerspace in Halle, Germany, I just had to make a printable version of this. I changed everything a bit to fit to my personal preferences better, so the general form now reminds me more of a Gnu than an elephant, so I changed the name accordingly. But the credit is due anyways, you will find the original design here (german page):
It now has a nice base plate with an easy accessible, slightly lowered area to put small parts into, without the risk of having it roll out. Feel free to modify.
You will need two standard clothespin springs for the assembly. Four M3 bolts with fitting nuts are helpful, too, but not required.
I added three different bases, just choose which one you prefer the most.
Print two upper clamp parts, two lower clamp parts, connect both with a standard clothespin spring (as can be seen on the attached photo).
Use four M3 bolts to attach the clamps to the base plate, the clamps feature little traps for the M3 nuts at their base. You can use glue if you do not have any M3 bolts lying around.