In the boot: dog bed, duvet, two fleece blankets, my towelling dryrobe (which dh didn't take out the other week before putting dogs in and I haven't taken out and washed since)
Storage compartment in boot: emergency waterproof poncho, folding dog bowl, water bottles, tyre inflator
Storage box: big first aid kit, hi vis, torches, tow rope, etc
Front storage area: suncream, couple of packets of percy pigs, water, cereal bars, wipes, dog poo bags, masks, hand sanitizer, £50 in cash, pens, energy gels, hand cream, ratchet straps, paracetamol, spare bike light
Strewn across the back seat: dry robe, towel, flip flops, shortie wetsuit, swimming bag (hats, cossies, goggles, fins), emergency paperback, umbrella
There is probably more as well. My car is an extension of my house really