To further decorate envelopes I send out for my web shop, I designed this rubber stamp with my logo.
I know there's not much use for you to have my logo, which I won't include, but maybe someone could use the handle or just the idea. I'm especially loving how the fingerprinty lines came out! That's done using a concentric infill on the initial layer in Cura and also the reason why some of the lines are not that straight in the print. I printed it oriented the other way you would normally do to avoid overhangs, so I the to be stamped part was touching the build plate. This is to ensure a good printing stamp. Orienting it the other way (stamp design up) will result in an inferior stamp quality. And since the lines that didn't print so well aren't touching the material you're stamping on it doesn't really matter.
The handle fits a 30x30mm stamp. To a certain extend you can scale and stretch it to fit your needs.
Monoprice Select Mini & Creality CR-10
The stamp itself is printed on the Monoprice Select Mini with Robin Reiter's flexible filament upgrade (https://www.thingiverse.com/thing:2029972 and https://www.thingiverse.com/thing:2030554), using Recreus's FilaFlex Skin II filament (230°C nozzle, 50°C heat bed, 120% flow, 20mm/s).
The handle is printed in Das Filament brown PLA on the CR-10 (210°C nozzle, 50°C heat bed).
To get those cool fingerprint like lines, tell your slicer (I used Cura) to use concentric lines on the initial layer.
To make the stamp I took my logo, brought it into Illustrator and saved it as an SVG, imported it into Tinkercad and gave it some depth. Then I added a cylinder on top to connect all the floating parts. This made the print a bit messy, as the flexible filament has a harder time bridging, but it came out well enough to work. You might not even need to do this, depending on your design. The handle was a quick sketch-and-pull job in Fusion 360, just guessing and eyeballing a bit, but it worked fine as well.