Calzone fillings

[msmofet]

spinach, mushrooms, ricotta and mozzarella

ham, swiss, ricotta and mozzarella

ham, pepperoni, salami, ricotta and mozzarella

sausage, red and green peppers, onions, ricotta and mozzarella

bacon, sausage, egg and cheese

[Andy M.]

Actually, anything you'd put into a submarine sandwich roll would work in a calzone. Condiments not necessarily included.

[FancyFiance]

Also just think, any pizza toppings you've ever seen will work, even weird pizzas like mac and cheese or hamburger. And anything you've seen in a hot pocket, like ham cheese and egg!

[letscook]

Favorite here is,
cooked bacon, ham, cheese

[Vanilla Bean]

the combinations I love...

spinach, mushrooms, cheddar or mozz
sliced turkey with spinach, mushrooms, cheddar or mozz
mushrooms, onion, olives, artichoke hearts and Fontina Cheese
sliced ham with onion, mushrooms, roasted red peppers and Havarti cheese
salami with ham, onions, peppers, artichoke hearts and mozz cheese