A few weeks back someone posted about some make ahead breakfast sandwiches that they really liked and they seemed easy to make. I have it in my head that it was kdrake8 and/or ladybug (But maybe I'm wrong about the people)
Wasn't me, but I always do breakfast burritos. Scramble eggs with sausage and cheese. Veggies are delicious to add too. Roll up in tortilla, wrap, and freeze. Minute in the microwave and they're great
Not sandwiches, but I make like omelets in muffin pans. You can put all random things in them. In going to make some today with hash browns, red and green bell peppers, spinach and turkey breakfast sausage. They are super easy and great for on the go.