I don't know if some of these were said already b/c some are known by more than one name, but there's also the:
Bandogge Mastiff
Dogo Argentino
Great Dane (german mastiff)
Indian Mastiff
Danish Mastiff (Broholmer)
Calabrian Cane corso (different breed than cane corso)
Mastiff of Terceira (easiest name to spell)
Cane Garouf (alp mastiff)
Chein de Trait (belgian mastiff)
Cypro Kukur (Kumaon mastiff)
Cuban mastiff
Maltese mastiff
Abruzzese mastiff
I guess it depends on if you are looking for those dogs just with Mastiff in the name, or those that are of mastiff type. I think there are many more mastiff type dogs, such as the st. bernard and newf that probably have mastiff in them, but aren't considered mastiffs today. I got most of the breeds listed off of
http://www.moloss.com/ but there are many more on that website that I think could be considered mastiffs, it just doesn't say in their name.