The official BSA Individual Campout Checklist for Pack Overnighter can be found here.
Below is a a bit more targeted towards our pack campouts, but it is a minimum and still a work in progress.
At a minimum Every scout should have the following.
Flashlight
Water Bottle
Whistle
Personal first aid kit.
Sun Protection (Hat, Sunblock...)
Trail snack (do not store in tent.)
Sleeping bag
Sleeping pad
Pillow (optional)
Shirts
Pants / Shorts
Underwear
Sleep clothes
Extra change of clothes
Cub Scout Uniform
Jacket (warmth)
Rain Gear
Toiletries (Toothbrush, toothpaste...)
Mess Kit (Plate, bowl, cup, silverware)
Every Family should have the following
Tent (including ground cloth and rain fly.)
Food for any meals not provided by the pack. (Do not store in the tent.)
Cooking gear if you need more than a basic camp stove.
Bug repellent
Extra blanket
Fishing gear (optional)
The pack will bring
Pack first aid kit
Camp stove
Pot for hot water
Firewood
Charcoal
Water bucket for fire
Shovel for fire
5 Gallon Water Jug (Drinking)
Wash Basins (Soap, Bleach, Rinse)
Hand washing station
Trash Bags