Paper Towels for cleaning bird poop off windshield and vomit from car and people.
Metal Water Bottle full of water to keep yourself hydrated. Also for self defense.
Tweezers, pencils, pens can be used for self defense to poke. Keep tweezers and golf pencil in driver’s side door handle. Keep pens in driver’s side door cup holder.
Car hammer (glass break tool, seat belt cutter), can be used for self defense and can break the side window to escape if the car is going underwater. The metal posts from the headrests can also be used to smash out the car window if the car is going under water. Strike at the corners of the door windows to break the glass.
USB charging cables, both Apple lighting and Android micro USB for your customers who’s cell phone batteries are dying.
Spare USB charging cable for yourself when yours goes bad (this happened to me)
QuikClot bleeding control gauze. You can never be too prepared.