Pizza is world cuisine now. Italian’s didn’t even start using tomatoes until the late 1680’s and the first major publication of a tomato sauce recipe wasn’t until 1790. The modern version of pizza wasn’t being made until the18th century in Naples. Margarita pizza wasn’t a thing until 1889. The Hawaiian pizza was first recorded in Canada in 1962. I would say anything can be considered a pizza topping especially because pizza now has over 20 distinct styles and an infinite amount of toppings. That’s what makes it so special.