My children like wraps (little chopped lettuce coated/tossed in salad dressing w/ turkey or various lunch meat and cheese in a tortilla). Or spread the tortilla w/ a savory/spiced cream cheese and lunchmeat. They like precooked (cold) quesadillas, pepperoni/cheese ritz cracker sandwiches or lunchmeat/cracker sandwiches, bagel bites, blueberry toasted bagel w/ peanut butter and jelly (son's favorite!), homemade pizza bagels/English muffins, Making banana or pumpkin quick breads, slicing and freezing individual slices, makes it easy to pack in a lunch. Although, not totally healthy, my daughter loves mini croissants (found at Costco in bakery section) spread with a little butter, slightly salted and served with a string cheese stick. I buy a package, butter and salt them, in advance then freeze them individually.
Usually the thermos comes out in the cooler months for soups, ramen noodle dishes, etc... Packed with a few crackers and a side of fruit, and you are good to go!
If you go to a GFS (Gorden's food service), you can buy a sleeve (50 or 100? - I don't remember the pack size) of 2 oz. souffle cups and the lids. Other places sell them but you have to buy a much larger quantity. These make it easy to pack little dips for stick pretzels, carrots, celery, graham crackers, packing salsa for baked corn chips, cut up apples with apple dip (yum!) small servings of raisins or trail mix, etc... I still wrap cup and lid w/ saran wrap so it doesn't pop open in the lunch bag.
My children's lunches consist of sandwich/main dish, one salty side or fun side dish (a carb), one fruit/veggie side dish, small bottle of water.
My children are good eaters and, believe me, I definitely "hear it" when I pack something that my children don't EVER want to see again. All ideas, above, have been "kid tested and approved!"
Hope this helps. Enjoy!