I know exactly what’s in the trunk because my car is fairly new.
1) A large bag of smaller plastic and cloth bags required here for “green” grocery shopping. I rarely remember to take one into the store!
2) A tote bag filled with roadside emergency “musts,” few of which I’ve never used. Includes flares, two first aid kis (I love first aid kits!), various lengths of stretch cords with hooks, and more.
3) A reflective window shade which I can’t use because it was custom-fitted to my previous car. It cost me so much that I can’t bear to toss it.
4) And my prized auto gadget… a pump that attaches to the cig lighter that allows me to inflate the tires. I’ve NEVER used it, despite faithfully having stowed it in a succession of car trunks over the years.