Non-seafood Dishes at Sushi Restaurants
My family loves "kaiten-zushi" (the sushi on the conveyor belts) and we go somewhat frequently. When I first arrived in Japan, the choices on offer at most restaurants was almost exclusively seafood-based. However, a multitude of choices are available these days.
As for non-seafood sushi, you can find the standard cucumber rolls ("kappa-zushi"), natto rolls, and omelet sushi ("tamago-yaki"). Some more trendy choices include pickled vegetables (eggplant is popular in my area of Japan), proscutto with sliced onion and Italian dressing, mini teriyaki hamburger sushi, roast beef sushi, broiled beef or pork sushi, and fried chicken sushi, among other choices.
There are a wide variety of non-sushi, non-seafood items also available as well. For example, you might see a basket of fried chicken or fried potatoes on the conveyor belt, or maybe a ceasar salad, edamame beans, bowls of seasonal fruit, cake, and so on. You can also order udon noodles from the menu at most sushi restaurants as well.
The new "kaiten-zushi" restaurants offer so many choices that everyone in your group or family is bound to find something they like!