What kind of pizza? My mother's taken to buying premade dough and doctoring up the dressings at home; the main version is a little bit of very salty cheese, usually feta, and a finely sliced onion.

Oddly enough, tuna on pizza works well, but you have to get it canned, and put it on before it goes into the oven. Also oddly, the suggestion is even more polarizing than anchovies, even if more people are okay with eating tuna.