Collocations for cereal - noun

crop, foods, grain, products
production

breakfast
bran, high-fibre/high-fiber, rice, wholegrain
fortified
fortified breakfast cereals
a wholewheat cereal fortified with vitamins

sugary

bowl
a big bowl of cereal

box (AmE), packet (BrE)

eat, have
I have cereal for breakfast.

bowl
box (AmE), packet (BrE)