Flashlight. That's key. And jumper cables. And a jack and a lug wrench

 

I carry with me a socket set, a tool box filled with odds and ends zip ties, at least one of every fluid she needs (except oil I carry three of them) a mat to lay on ,a heavy coat a pillow for my dog a back pack jack and tire tool tire pump and a pair of cleats and boots lol.
I believe in redundancy whole heartedly .