What are some good vegetarian riceball / onigiri fillings?

Question

Besides a pickled plum.

Answer 1

Fruit - kiwi, mango, avocado

Veg - cucumber, corn with mayo

Answer 2

roasted red pepper, bean sprout, carrot, ginger, avocado...

Answer 3

Pickled ginger, daikon radish, sesame seeds and furikake mix, burrdock, I use surimi with Kewpie mayo, edamame, bean pastes sweet or savoury.

Shiso or perrila leaves, I use non Japanese items like kimchees and pickled korean veg mix.