This website provides a nutrition breakdown of 20 popular cereals brands, including Cheerios, Corn Flakes, Froot Loops, Lucky Charms, and Cinnamon Toast Crunch.
Each row in the Data tab shows nutritional facts (Calories, Total Fat, Sodium, Total Carbs, Fiber, Sugars, Protein) while also including the serving size for each brand (in weight/amount) to allow for accurate comparison across products. The goal of this resource is to easily compare popular breakfast cereals based on the nutrition data!
I will note that some of these nutrition fact data may be outdated, so I would double check the information if you are looking at a certain brand.