Yes, I carry a small maxpedition bag with many of the items already mentioned and more. Some if it is stuff i use frequently, and some is just in case items. It doesn't stay in my car. I have separate items that do stay in the car.
NRA Certified Pistol Instructor & RSO, IDPA Sharpshooter, Project Appleseed Rifleman
Member NRA, GOA, SAF, VCDL