Well my mother says to have chhatua for breakfast which has all sorts of grains and other healthy stuffs. But I have rice flakes and milk.
Have prepared some over night oatneal with berries. Fruits or something that contains granola. Yogurt. Are all good options
Things you actually need are best, I often find myself taking random stuff and putting it into my backpack because I come up with crazy situations in which I need it.