S.F.
Get a good ice pack, insulated lunch box and things will stay fresh and cool. You should be able to send most things that you make at home.
-yogurt, cottage cheese, string cheese
-hard boiled eggs
-fresh fruit
-veges & dip
-any type of sandwich
Get a thermos and you can send hot foods. Just put hot water in the thermos for 5 minutes, empty out the water, add the hot food and that will keep it warm until lunchtime.
Thermos foods...
soup, stew, mac & cheese, leftovers