Cereal makers are responsible for the production of breakfast cereals. POST, Trix, BRAN, and OAT are all cereal makers. POST is an American cereal maker that produces a variety of cereals such as Honey Bunches of Oats, Fruity Pebbles, and Alpha-Bits. Trix is a General Mills brand of cereal that is known for its colorful shapes and fruity flavors. BRAN is a type of cereal made from wheat or oats that is high in fiber and low in sugar. OAT is a cereal grain that is used to make oatmeal and other breakfast cereals.