We spent weeks making sandwiches before we realised it’s impractical to carry loafs around. So we now only buy tortilla wraps. They’re a little bit more expensive, but they fold / roll up to nothing and are less heavy in the tummy.
We generally make one savoury and one sweet wrap each lunchtime. For the savoury one we generally use tuna and / or eggs (which we boil in the morning to carry without breaking them). We add whatever fresh veg we have, like bell peppers, onion, Roma tomatoes, lettuce etc. We make them interesting with our stock of flavourings; oregano, garlic powder, Parmesan (from a shaker), sweet smoked paprika etc.
Our sweet wrap never changes! We have peanut butter, jam and banana every day. We love it. It’s super cheap and gives us loads of energy.