Some Brother printers still support 10.3. A friend with a circa 1998 G3 PowerBook running 10.3.9 recently bought a new Canon inkjet and it works perfectly. You have to go to web sites and see what is called out for the min sysreqs.
Also, forget multi-funcitons. They almost all want a much higher OS than you have.
Assuming you are in the market for a black and white laser printer, Brother claims the 2170W (which I own) will work even with OS 10.2. But I do not know if that model is still being sold.
To check on any Brother printer, go to the site and navigate to the driver downloads page:
To find out what OS is supported select a printer and check what drivers are available.
p.s. I happen to like Brother printers. They are often on sale for $60 to $70.