Furikake, according to my Japanese dictionary app called Midori, is "dried food sprinkled over rice". I have seen it several times used in onigiri, as topping on rice and spaghetti, and as ingredient in other dishes like tamagoyaki. There are numerous kinds and brands of furikake, but most have katsuo (bonito) and other kinds of meat and seafood in them. A strict vegetarian Japanese woman (the owner of the vegetarian restaurant I worked for a few months ago) taught me about this vegetarian furikake. One time before I left her restaurant, she just handed it to me and said it's vegetarian. After I tasted it, I immediately searched supermarkets for this kind (the supermarket near our home didn't have it).
These three kinds of furikake by Marumiya 丸美屋 (pictures above) are the only vegetarian types I know that are available in the common supermarket (as of now). Each pack is sold for ¥98-¥120, depending on where you're buying it. My and my husband's personal favorite is the one with wakame seaweed, dried ume or Japanese apricot, and shiso (leftmost picture above). I usually eat it as flavoring to my rice. It's ingredients are wakame, salt, sesame, ume, shiso, wheat flour, yeast extract, starch syrup, palm oil, amino acid, seasoning, red cabbage pigment, sodium acetate, sodium carbonate, and something that's not written in my dictionary (ミョウバン・myouban). This is something I and some other vegetarian friends bring when we are on trip and don't have much choice on food.
If you're traveling somewhere not so vegetarian-friendly and wishes to eat more than plain rice just for energy, I strongly suggest getting a pack of furikake. It definitely won't give you the nutrients you need, but it will give visual and gustatory sparkles to plain rice. And daisy-field-like joy in rice ball. Oh, I just want to clarify here, I don't get anything from advertising their product here. This is just to help fellow vegetarians to survive a currently (mwahahaha!) meat-eating world-- until I launch my Green Green Grass of Home World Domination Project. *reverberating evil laugh with meat-eaters on the background with shaky knees* Furikake for you, Kahki. (Oh come on, give my ending a smile at least!)