I have a pair of scissors. I trim threads with it. Fabric is always cut on a mat with a 6x24 ruler and a large angled rotary cutter. Saves on the wrist. i have no idea how you would cut straight lines without this set up.
As far as 'must have', groovy boards for my long arm. I now make them myself in my shop. I guess I have turned into a sophisticated quilter. tim in san jose