This is often the easiest food to add to a lunch, especially if you plan ahead. Leftovers from the night before are very valuable because they are prepared fresh buy yourself and don't contain nasty preservatives that are designed to extend the shelf life of the food, plus it's a very practical way to minimize waste and expense and you know exactly what's in it.
The great thing about wraps is that the "wrap" can be so many different things. While the most obvious is a tortilla (preferably whole wheat and sprouted), other choices include toasted nori seaweed sheets, crepes or a large leaf of lettuce. Here are some easy creative inspirations:
Soups offer the ultimate nutritional bang for your lunchbox buck. They fill the belly and warm the soul, especially on those cold winter days. These lunch items are particularly nourishing when made with a homemade bone broth base, which is bursting with vitamins and minerals, including calcium, magnesium, collagen and much more. Freeze leftover soup in meal-sized portions (glass Pyrex or small plastic yogurt-size containers work well). Thaw the needed portion overnight and warm it up on the stovetop (ideally stay clear of the microwave) for the (stainless steel) flask.
A well nourished school kid will be happier, healthier and more academic so its important to put a bit of time into their lunch box.