In our quest for truth, I googled pizza and found some good stuff. One idea was something I was already struggling with: what are the "other" things that are often sold in a pizza store (from remnant dough).
Wikipedia calls this Structural Variations, to wit:
I add: sausage rolls.
Also: Ethnic Variations: Greek pizza, Lahmacun
, Sicilian pizza
Also: Miscellaneous Variations: Tomato pie, Pizza bagel,Grilled pizza, Deep-fried pizza, Garlic fingers, Hawaiian pizza
Also: In the 20th century and onward, pizza has become an international food and the toppings may vary considerably in accordance with local tastes..diverse choice of ingredients, such as anchovies, egg, pineapple, banana, coconut, sauerkraut, eggplant, kimchi, lamb, couscous, chicken, fish, pierogies, french fries, shellfish, meats prepared in styles such as Moroccan lamb, shawarma or chicken tikka masala, and non-traditional spices such as curry, cilantro, cumin, and Thai sweet chili.
Now, RFers, we know as much as Wikipedia. What to you want to add?