well, those do exist. Meatballs are a very classical, and very essential Italian dish.
probably not commonly found with spaghetti, but can be found as complements to many types of dishes, even pasta. Pasta overall is treated differently, though, in Italy when it comes to the meal.
I think Alfredo is limited to one very tiny region in Italy and nowhere else. I forget which, but no one outside of that area eats it. I think it's popularization over here is definitely misguided.
I love Italian Bruschetta and I make it frequently--at least, Toscano, which, in my experience, is simply old, toasted bread, topped with tomatoes, garlic, basil, and drizzled in olive oil. So good. Especially with thick-sliced bread. toasted/fried on both sides and retains a soft center.