with my xh I used to do lunches for him when he was doing a 12 hour shift at work - so not only lunches I had to do snacks as well.

Lunches:
pretty much anything that we had for dinner the night before, I also used to do up things like macaroni cheese, lasagne, stir fry, steak & veges, tuna pasta bake, etc & package them for re-heating in takeaway food containers.

For the snacks, I used to do three or four different batches of bikkies on a sunday and package them up. Or cheese & crackers (I used to slice up cheese into thin blocks for him & he'd take some crackers from home), he also used to take those small tins of tuna.

I'd also give him an iced coffee, plus coffee makings in the cooler bag.