I have used a teflon sheet, intended for ironing to keep sticky stuff off your iron when doing fusible projects. I attached it to the bed of my Singer 15-91 with painter's tape. It really helped the quilt slide, but it isn't a perfect solution since the tape has to be reapplied frequently. I have some gorilla tape, but hesitate to use it on my machine.
I have since mounted that 15-91 into a cabinet, so I may be in the market for a supreme slider or equivalent myself.