I have been using this 3d printed bench vice soft jaw I designed since 2016. I have printed them in PLA and PETG for several people, both materials work equally well if printed with enough perimeters and good layer adhesion. Recently I remodeled them in Onshape as a fully parametric model. Just enter the measurement values as the parameters about the vice jaws (left hand side top of the design tree in Onshape), and the model will self generate. You can configure the magnet size, jaw width/depth/height, etc.
Hope you can find it useful. I have found they work great for holding materials in the vice you are afraid of damaging with a standard hard/knurled vice jaw.
I have included an STL and STEP model dimensioned for my bench vice at home. It has a jaw depth of 12mm, height of 22mm, and width of 140mm (aka 5.5in). It is designed to use a 10mm diameter x 5mm thick magnet which are available at most hardware stores. Any other configuration people mention wanting I can also add upon request. Otherwise please hop into Onshape and modify to suit your needs.