I have remixed two Prusa Printers stands for the I3 and Mini plates. You can have two sheets for each machine.
https://www.prusaprinters.org/prints/26167-prusa-steel-sheet-holder/comments
https://www.prusaprinters.org/prints/25512-prusa-mini-sheet-holder-4-printable-on-mini/comments
PETG.
20% infill.
0,3 mm
The author hasn't provided the model origin yet.