Recently I was gifted a Gerber STL 2.5 Drop Point Fine edge knife.
This blade was so insanely handy for stripping coax, I just had to take it to work with me (which is pretty much everywhere)
So I made a magnetically retained holster for it.
Best suited for 30-35mm wide belts.
I suggest you print it vertically (as shown) with support columns.
If printing in ABS, an acetone dip is highly recommended for strength.
You will also need a 10mm diameter, 1.75mm neodymium magnet.
This should stay in the slot just from the tight tolerance alone, but if not, use a touch of superglue.
The thumb slot is modeled on my rather sizable thumbs, if you want to remix this, let me know and I'll post source files.
Inventor IPT file already included.