One of the sandwiches we do on days we don't have leftovers is a broccoli melt.
Chop up broccoli in small pieces, saute it in some oil until it is barely tender. Add some herbs or garlic if you want. Pile the broccoli on bread, lay some cheese slices on top, and run under the broiler until the cheese has melted or, depending how hungry everyone is, the tops are browned.
To be super-quick, you could saute the broccoli ahead of time, even in a big batch for several lunches.
Here we ate our sandwiches with red beet eggs.