We have two children with varying degrees of motion sickness and these always come in handy
Wet wipes and hand sanitizer
Chances are the kids are going to want to eat snacks on a long drive, so having wet wipes available to clean up before and after
Self explanatory, but can also be used as toilet paper for an unexpected “emergency”.
Not many of us will forget to bring one, but use it to download handy travel apps and maps.
Most cars have the ability to charge devices, but just in case, I like to bring along a portable charger and plenty of cords.
My kids could spend hours just taking photos out the window or at various stops. It gives them something to do and I use the camera when we get to our destination.