There are a lot of other Vice models here, but this one is mine. I like it because it looks cool (to me), is 100% 3D printable (without any supports) and works well for my purposes which is to hold Pi Zeros and their pHats for soldering, etc. The "jaws" have triangular grooves for confidently holding things like circuit boards both vertically and horizontally.

The assembled unit (when jaws are closed) measures about 161x70x90mm. The space within the jaws when fully open measures: 67x70x70mm (can hold a Raspberry Pi Zero in any orientation).

To assemble, you require 1 print of each part and 4 prints of the 10mm bolt.

This isn't meant to perform apply super heavy compression, but could certainly pinch a finger pretty hard or worse, so, use at your own risk!

Print instructions

When slicing each part, make sure you orient any piece with a screw thread to print the thread perpendicular to the build plate with these orientations:

Main Screw: Print with the thumb-screw/knob on the print bed, hole at the top;
10mm bolts: Print with the thumbscrew on the print bed;
Main Screw End Cap: Print flat on the bed with the screw threads oriented vertically;
Screw Plate and Back Plate: Print flat with the screw threads oriented vertically;
Idler Plate: Print upside down with the "top" of the piece on the print bed;
Base Plate: print vertically with one set of screw holes on the print bed, the others at the top.