Are any of those printers inkjets? I think tracking dots are strictly a laser printer thing.

Tracking dots (or lines, or barcodes, or whatever other technique) are not unique to laser printers. They are also not the only surveillance technology built into printers. There's digital watermarking, steganography, CDS, telemetry, and even logs kept in local memory/storage.

Can you link any examples? Very curious to learn.

Nope. Some even refuse to print black and white when yellow ink tuns off.