This is a thread die holder for 25 x 8.5 mm dies. 

You may arrange individual holder samples to layouts of e.g. 8x1 or 5x2 in your slicer, or glue individualy printed samples together. As a shortcut I include a 10x1 layout .stl.

Each die is held in place by two 3D-printed springs. 

The cavities are tilted by 45 degrees, so you can directly read the die size (e.g. "M12   1.5") provided you have rotated the die approprietly. 

Todo:

The OpenSCAD source code is still an incredible mess. I will publish it as soon as it will stop embarassing me in public.

Support for different diameters (e.g. 20 mm). As a stop-gap solution you may scale the .stl in your slicer, but I haven't tested if this works with both die diameter and die thickenss.