All vegetables are fair game. The best are the most obvious, but odd ones are interesting, too: green (spring) onion, carrots, cucumber, greens and lettuces of all kinds, bell pepper (roasted or raw, whatever colors are available), jicama, daikon or other radish, beetroot, taro, or whatever you have lying about. Just make sure the veggies are thinly julienned.

I've also made fruit sushi, which I have been told is taboo. Not sure why that is since avocado is a fruit and is used in many rolls. It may take most palates a bit of getting used to vinegared rice and seaweed with fruit, but apples, mango, and peaches are my favorites.

All edible varieties of mushrooms are good additions. They, too, should be thinly sliced; the exception is enoki which is too thin to cut.

One other traditional ingredient deserves mentioning. Rather than rolling a scrambled egg in with my food, I use scrambled tofu.