What supplies did the escaping Gladers take with them?

The Gladers pack serum, food, and other supplies for their escape.

Backpacks were handed out and stuffed full of supplies. Frypan—Newt told Thomas that the Cook had been one of the last Keepers to agree to go—was in charge of gathering all the food and figuring out a way to distribute it evenly among the packs. Syringes of Grief Serum were included, even though Thomas didn’t think the Grievers would sting them. Chuck was in charge of filling water bottles and getting them out to everyone.