Hmm, for cutting sandpaper I've an old hacksaw blade attached to the
edge of my workbench. I slip the sand paper behind it and tear as needed.
John

Mike Paulson wrote:

From the dollar store, a large scissors that I use to cut sandpaper sheets
into squares and strips. Cuts through 4 sheets at once. Been using it
since forever, not sure I ever had to resharpen it.