Is it for a child or adult?
Wrap or pitta bread with various fillings: falafel, grilled halloumi, bean chilli, sour cream, salad...
Cheese or boiled egg salad
Pasta salad with pesto, cherry tomatoes, pepper, beans if you fancy, cubes of feta or chopped up mozzarella
Boiled potatoes with mayo and various salad veg
Mixed bean salad
Put lentils with sundried tomatoes and mozzarella
Cold omelette sliced up with salad
Sliced of cold quiche or a mini quiche/pie/pasty and salad
Oatcakes with cheese and crudités and a bean dip or houmous