Ideas on a good breakfast for concentration?

I keep feeling tired and unable to concentrate at work, I'm starting to think this is maybe because i have a poor breakfast, such as a few slices of toast orf a sandwich on the go.

any ideas on something to keep you awake and focused, at least until lunch time?

I have oatmeal for breakfast nearly every day. I soak the oat, and some sunflower seeds over night, then rinse them the next morning. I might add some dates, some maple syrup, or any kind of fruit..

It varies what I have for breakfast but I usually feel the best after having a smoothie (banana/flax/maca/omega oils/pea-rice-hemp protein powder/agave syrup/+other fruit of choice)

Smoothie. Fruit, milk, flax, all blended up...

I have a green smoothie almost every morning: baby spinach + banana + frozen strawberries + flax + protein powder

I have oatmeal with banana, cinnamon, agave, and a little peanut butter mixed in. This works well and carries me for a couple of hours before I need something else to eat.

I have oatmeal with flax seed and peanut butter, and a tofu scramble pretty much every morning. If I need a little kick in the seat of the pants, I'll drink a cup of yerba mate.

Oatmeal or Quinoa, fruit and whole wheat toast. I eat about 6:30 and that'll keep me until about 10:30 or 11:00 if I can't get anything in before then. Concentration is a big problem for me generally. A solid breakfast helps A LOT.

I feel like what helps me concentrated, what nourishes my mind, and encourages clarity is to have a handful of soaked almonds right after dinner and a cup of blueberries in the morning. I pack a piece of toast with almond butter for school to keep going, but the blueberries and almonds are like my 'super' brain foods that I have to have to keep me mentally in gear.