npub1pf8pq0padrg9yjyl7tac68pnkalxrt5rcdp554u4tuymz4zm85dsgxxnze (npub1pf8…xnze) iirc it's mostly color laser printers. BW laser printers and inkjets are not yet known to contain tracking codes.
Ofc there may be tracking on these other printers and we just haven't found out about it. As far as I know there is no open source printer, crazy that we can get open source 3d printers but not open source regular ones...
Let me know if you find anything, I haven't checked in on this in a while.