A parametric soft jaw I designed for my 5" bench vise. The OpenSCAD file is parametric so you can adapt it to your own vise's measurements.

I printed this in eSUN PLA+ at 50% gyroid infill. You could use more durable materials, but I'm pretty happy with it right now.

Modifying

Modifying the OpenSCAD file requires you to install BOSL. Important parameters to tweak: 

JAW_WIDTH=126.5; JAW_HEIGHT=18; JAW_DEPTH=5;