I used to be in a similar situation. I would sometimes do sandwiches, I'd buy the small croissants & fill them with turkey & cheese or chicken salad. The croissants were so rich that you didn't need condiments.
Some good salads were Taco Salad or Chinese Chicken Salad. Prepare everything & mix right before serving. I'd make pasta salad with tortellini & add pepperoni, salami, cheeses, black olives & that was always a hit.
The girls always loved bean & cheese burritos too. Make them up & keep warm in one of those insulated bags. They didn't need to be hot to eat & they were always a hit (not my favorite, but they loved them!)