My favorite pizza when I was working at a pizza/sub shop was spinach, onion, bacon, feta cheese and fresh garlic. Also, where I'm from they make a spinach pizza (cooked spinach mixed with ricotta, feta, egg, olive oil & garlic) topped with Mozzerella.

They still taste great without all the crust!

The spinach/ricotta mix is good baked all by itself and also stuffed in mushroom caps, or on a portabello. I am actually making some tonight!! Yumm