DD has food intolerances & is pescetarian, so packed lunches aren't the easiest, but its better than trusting the new School meals provider, who IMHO/IME are totally cr@p 
, also theres nut allergies in School to take into account, so it can be difficult some days
Today shes gone off with a tub of veg snacks, sort of salad, but more carrots, mange-tout, peppers, olives, spinach leaves, butter beans & a chunk of mature cheddar (she can't eat mild cheeses), - most of which I just cut extra of as I was preparing tea last night - also another tub full of proper corn nachos & a home made blue berry muffin & a pear.
I rotate between making batches of maki rolls - pasties are good as you can either make them up & freeze & pop in the oven when cooking tea the night before & generally just a good back up, I make up batches of fruit muffins, or fill little lidded pots with fruit & jelly & keep a stack in the fridge to just grab.
She's also happy to have cold plain pasta as her carb with grated cheese & again a chopped veg pot.
She gets sandwiches some days, but I have to remember to buy bread/rolls as can't send her in with our normal seeded stuff, but she's limited in what she'll eat in a sandwich, as she complains the lunch bags aren't stored well, so if its hot some things don't taste so good, so its mature cheese & pickle, or tuna & sweetcorn mayo.
Couse cous or rice salad is another I make batches of & it can last a couple of days in the fridge, so easy just to throw a scoop into a tub