A simple, easy to print rubber stamp 50x25 mm (but should be simple to scale to pretty much any reasonable size). The handle is PLA (or ABS), the base is TPU (any flexible filament should work). I have included a few commonly used stamps (RECEIVED, PAID, ACCEPTED, REJECTED, SCANNED) but any 50x25 mm base will work. Print or carve your own and attach with a few drops of glue to the handle (remember to carve your potato mirrored ;-) ).

I use generic PLA at 0.2 mm layer height with 20% infill at 205 C for the handle and TPU also at 0.2 mm with 30% infill at 230 C for the bases. On my Ender 3 the bases print in approx. 20 mins, the handle in 30.

A quick note: you will get better results if you SAND THE BASE (the side with the text on) after printing to get a fully flat surface.

Ender 3

Doesn't Matter

No

0,2

Doesn't matter