I would like to vouch for Xerox laser printers. Not only they don't identify your printouts with tiny yellow markings/serial number, but also they gladly accept off-market toners, and places like Amazon have many different brands that race to the bottom of price making it easy to try out what works for you. I am on my third Xerox laser printer and couldn't be happier.
I bought an awesome Xerox duplex colour laser two years and can confirm. Superb. Way better than the Samsung/HP thing it replaced. About to put more after-market toners in tomorrow