Little LED flashlight, even the parks are not brightly lit and you might need it to see some detail, or if you drop something etc. Definitely needed for Fort Wilderness.
Extension cord or power strip for all the chargers. Most of the outlets are along the floor.
Ziploc bags if you get snacks to take back to the room, or keep them in the room and need to keep them fresh.
Clips or clothespins for the clothes line in the shower.