You want something easy and filling. Carbs is the worst for bfast because it'll only make you hungrier after 2 hour. Slow-digesting fibre and protein is the best.

Overnight oatmeal - prep it before you go to sleep. Wake up and ready to eat, or take with you to office.

Recipe:
- 1 cup oatmeal (rolled, instant, steel cut, anything will do)
- 2 cup milk

that's it. You can go fancy and add dash of cinnamon and honey, banana. Let rest overnight in fridge.

Other than that, boiled eggs always work for me. I boiled 10 eggs at a time and take 1-2 each everyday to work. Sometime I have boiled eggs as snacks.