I actually did a make your own pizza party a while back, I encouraged people to get weird with it and a lot of my my friends are kind of foodies, so here's a couple standouts

Goat cheese, hot honey, fig preserves, and capocllo

Spicy hawaiian - grilled pineapple, bacon, ham or spam, jalapenos, drizzle of hoisin sauce

Mac & cheese

Taco- taco meat, cheddar, red onions, jalapenos, lettuce tomato

Cheeseburger - ground beef, cheddar, mustard, ketchup, pickles, onions

Desert pizza- pie filling, vanilla glaze, crumb topping

Sort of a knock-off flammkuchen- creme fraise (sour cream would probably also work fine,) gruyere, onions, bacon

Buffalo Chicken - chicken, hot sauce, blue cheese crumbles, diced celery, shredded carrots

Breakfast pizza- eggs (we used quail eggs because my pizza oven is on the small side and we could get them, just crack them right onto the top of the pizza,) bacon, sausage, hash browns

Chicken Tika masala

Greek- kalamata olives, feta, spinach tomatoes, balsamic

And of course we had all of the standard pepperoni, sausage, mushrooms, olives, peppers, etc.

A couple different sauces - standard pizza sauce, pesto, vodka sauce, Alfredo, etc.