I discovered artichoke hearts as a topping not long ago and I’m impressed with them. My top 5 are probably sausage, spinach, onions, artichoke hearts and tomatoes.
along the vegetable line courgette (zuchini in america?), thinly sliced lengthways is much nicer than you might think. Goes crispy and stuff
Alltime favourite is olives though
Seafood pizza is my long time favourite. It’s quite expensive compared to more common toppings, but I don’t eat pizza very often (around 3-4 times a year).
Depends on my mood what combination of ingredients i want but in no particular order, Black olives, mushrooms, banana peppers, jalapeños, sausage and pepperoni.
And way to much crushed red pepper on every slice 
spicey meat feast, pepperoni, or seafood with heaps of anchovy.
I love anchovy - almost in a nausiating Zoidberg way (draw the line at off-the-floor/dumpster/you-get-the-gist)
My favorites are salami and gorgonzola
and tuna, onion and feta. 
Thin crust, always thin crust.
Meat-lovers is a staple but chicken & spinach has its time and place.
Whatever is it, I’m definitely drowning it in crushed red pepper.
NO onions, no mushrooms though. You put that on my pizza and I KEEL you!!
I’m still trying to wrap my head around mac n’ cheese pizza. Like, why? Why would you put cooked pasta on pizza? That’s like making a sandwich with two slices of bread and a flour tortilla in the middle.
Pepperoni, Mushroom & bacon gogo! 
lol
Pepperoni, Black Olives, and Mushroom used to be my favorite for a long time.
Now on the rare occasions I have pizza its always some veggie mix - but I’ve yet to really pick a favorite, although artichoke hearts, zucchini, and olives are all staples of a good veggie pizza.
depends on the pie -
'Merican style, pepperoni and mushroom
If I’m at a ‘Chicago Style’ place, I skip the deep dish, but get a double-crust supreme (sausage, onion, olives, peppers).
Neapolitan style I keep it simple - margherita, mushroom n salami, or just basil.
In England, don’t eat the pizza, go get a nice curry instead
Oh damn i wish i didn’t read this
Standard:
Salami, Onions, Anchovis, Capers (optional: Olives)
Sometimes, here in Germany, we have some weird combinations. Once in a while I take something like this:
Christmas Pizza:
Barbarie Duck Breast, Red Cabbage, Apple Puree and a little bit of cinnamon
Greek Style:
Gyro, Spinache, Garlic, Shrimps and Tzaziki.
@ They Live:
For an Italian this thread must be pure horror! 
Why though? I wasn’t to Italy since 2010 but I think there also was a great diversity of toppings, some of which were quite exotic.
I only like to take some pizza to my cheese. I generally put much cheese, add some meat, onion, tomato, again much cheese (because I like pizza with my cheese). My family though likes a bit of cheese on their pizza and olives. We usually don’t put much ingredients on it.
By saying “much cheese” I mean MUCH, like there’s only cheese visible on the whole pizza, and sometimes you see a little bit of meat or onion, but rarely.
I have a few italian friends and they told me that these exotic toppings are more for the tourists.
If They Live is from Napoli he may be even more traditional. 
When I went to Malta a few years ago they had some strange combinations, too. But I´m the kind of guy who has to taste everything (at least once…).
Edit:
What kind of cheese? There are much differences in different countries.
I’m from Roma (or more precisely a town 12 km from it) but yeah…the horror… ( imagine marlon brando in apocalypse now)
But, if it helps you…I have never eaten such a good pizza again like I ate in Italy. No high class Italian restaurant here, not in the USA…never.
I’ve got a really good Italian place right down the street from me, actually, but they don’t do pizza to my knowledge. Their tiramisu is amazing though.
Pepperoni and sometimes Meat Feast are my go-tos.