S.M.
My daughter is in preschool and I have to pack breakfast and lunches for her. For breakfast I pack bagel w/cream cheese, yogarts, muffins, dry cereal and fruits.
For lunches I do "lunchables", we also do chicken nuggets, pizza rolls, cheese, applesauce, muffins, ham and cheese sandwich, pb&j if no allergies in school, pasta or anything left over from dinner the night before.
Snacks are usually pretzels, gummies, cookies, crackers, puddings, etc.
It helps a lot if they are willing to heat lunches for you. Luckily my daughters school will microwave. They also have a toaster oven if I want to send her a grilled cheese.