True, I throw a few blankets in the back seat. But I'm always suited up in winter gear. Snow belt. Lake effect overlanding.
I've got my suitcase with me anyways. No biggie.
Truck claws or tire chains. You'd be startled how well Truck claws help you out of an impossible situation. Like an unclimbable icey ditch.
Shovel
Brush
Bucket of chain, with hooks.
Fresh battery, and a spare battery if fullsize truck.
Rubber disposable gloves.
Small sledge hammer.
Extra lug wrench.
Small amount of wood.
Rotate your tires before winter, so hopefully the sledgehammer isn't needed much.
Drop your spare, to make sure your tire winch functions. (And that you know how it functions, if you bought a GM with the funky garbage latching style)
Find your OEM jack. Make sure it works still.
Denatured alcohol and a Pepsi can stove. Maybe some food, hot chocolate to keep the missus content, while I dig us out.
Spare wipers and wash.
Paper maps, if the GPS goes down, or goes stupid. Garmin GPS is worthless rerouting around Columbus Ohio gridlock. And some pot brained schmuck in a Prius causes a pile up, every Christmas.
Tool bag. If you're truck uses moronic battery clamps, in a bad spot, make sure you have a tool that works.
I don't see why I'd use my tent, if I have a truck.