I recently found out gluten was a source of trouble (probably coeliac but not confirmed just yet), so none anymore. However, for the first 30ish years of my life: cereal in a bowl with a spoon. Cinnamon Toast Crunch as an adult treat, other boring health cereals (some kinda bran thing, I think a Special K one at some point, etc.), and Alphabits a lot as a kid. Also sometimes Cheerios, Frosted Flakes, and others depending upon what we could afford. I would just have some normal beverage alongside it but I don't remember feeling particularly compelled to drink more.