My son likes when I buy the Purdue cooked breaded chicken patties (they come 4 in a pack, in the refrigerated meat area in Giant), they also come in a spicy version which he also likes. They seem to frequently be on sale. He heats up 1-2 patties in toaster oven, puts on a bun with mayo and a slice of cheese. Eats with chips and an apple.
Sometimes I make a large bowl of pasta salad with sliced pepperoni, mozzarella balls, diced artichokes and red peppers, whatever other veggies I have and toss with evoo/balsamic vinegar (or bottled italian dressing). DS will bring large tupperware of it and bring granola bar, small yogurt, etc.
Our main problem is finding a lunch bag large enough to fit his food and an ice pack, yet not be so large he can’t fit it into his backpack along with his other stuff.