When you mention "sushi" vegetarian and vegan options may not be the first ones to come to mind, but they are common and offer a refreshing dining experience.
Tamagoyaki (Egg omelet)
Fluffy and sweetened, this is popular among all sushi lovers. The tamagoyaki nigiri is bright yellow with a rigid thin seaweed belt attaching itself to the sushi rice.
This is an example where it's advisable to confirm with the restaurant whether any fish dashi (broth) has been added to tamagoyaki. In many cases, you can request it without the fish dashi.