I designed a multi-purpose survival utility knife that combines a knife with a lighter, a pencil, a spare blade and a few meters of duct-tape.
You just have to print out the plastic-parts and slide the utility-blade into the slot.
It is fastened with a small M3-screw.
Add some 4mm x 2mm rare earth magnets to the holes in the blade cover and the knife handle.
The hexagonal hole in the grip fits a pencil. I used one that you get for free at IKEA.
The other hole in the grip fits a lighter and a spare blade.
As the last step I wrapped the handle with a few meters of 50mm duct-tape.
I added the .stl-files with and without support.
I printed the version with support and simply trimmed the support material away with a knife.