A lengthened version of a top tray I found online for the P1S and P1P that utilizes the button hole to keep it in place. I altered it to be flush with the side of the printer and longer to utilize more of the unused space on top of the printer.
I have both a version that works with the normal P1S/P1P and one that works with SpectreGadget's AMS Glass Separation Riser (which I am using on my P1S). The normal variant is slightly larger due to not having to fit around a top glass riser.
Credit to Sesheron for making the original model.
Optimally, it is printed in the orientation it is currently in for the best finish. You will have to rotate it 45 degrees to get it to fit on the build plate, though.
The author remixed this model.
Lengthened the tray to take greater advantage of the unused space on top of the printer. Also created a version to fit around SpectreGadget's AMS Glass Separation Riser.