Key-sized Garmin dash cam that barely shows on the windshield and automatically saves the clip if there's an incident. Wide 140° view. A nice price for a Garmin. Deal may end at any time.
A jump starter and tire inflator in one, so you don't need to wait for someone to jump you on a freezing morning. Doubles as a USB power bank. A smart thing to keep in the car this winter.
Cold weather drops tire pressure. This cordless pump with a digital gauge shuts off on its own when it hits the PSI you set. Works on bikes and balls too. Keep one in the trunk.
Seals and inflates a flat in one go so you can get to a shop. Cheap glovebox insurance, worth keeping one in every car.