I experimented with plain paper, baking paper, greaseproof paper, oiled paper, but the best transfers were with my cheap label backing paper.
To economise on the amount of label paper, I cut a section roughly a bit larger than the PCB, and stuck it to a clean A4 sheet with some of the discarded stickers. This then goes through the laserprinter.
I then took off this section, bent it over the PCB and taped it down, then ran it through my laminator a couple of times. This transferred the toner to the PCB.
After etching, I had four new stepper boards to build