Not a 3D printer but really cool video by Stuff Made Here explaining how he tried to make 'realistic' handwritten forgeries with a pen plotter: https://www.youtube.com/watch?v=cQO2XTP7QDw
Yes, actually Bambulab (I know currently controversial) has just released a new printer (A2L) that actually has the cutter and pen functionality. You just clip it onto the printer head and it works.
(This is not meant as an advert for them, not affiliated in any way. It's addons that other manufacturers will also add to their printers)
open source license violations/takedowns of legitimate open source forks, and other anti consumer practices. casual users likely unaffected, unless you're philosophically offended (rightfully, imo)
CNC is CNC, if you can put an attachment on it, it'll probably work. If you replace the hotend with a router and make the extrusion wires turn the router on and off, you have a CNC router. If you use a swivel knife, you have a vinyl cutter
The printer calibrates, pauses, you attach the pen, press continue, and it'll do the plot without zeroing the Z-axis again.
https://www.stavros.io/posts/make-pcbs-at-home/