Here are the materials that are often added to a basic Taiwanese onigiri.
You can choose what kind of rice you want, there are often two kinds of rice the white and the purple one, some sellers will provide mixed grains for a healthier choice.
There must be a fried breadstick inside the onigiri that provides a crunch texture, and the pork floss provides the meat smell.
And the mainly salty materials are dried radish and pickled cabbage, the onigiri will add one of it. Some can choose spicy flavor.
The B part is any kind of egg dish, boiling egg, braised egg, soft-boiled egg, fried egg, shredded egg crepes, salty yolk, and green onion fried egg.