Essential if you are on the road, you might need to signal people you are having trouble.

Spare lamp for the flashlight.

To put litter on, convenience in an elegant way :).

Keep your car clean after having to eat stuff like crackers in there, or just day-to-day cleaning.

Better than having a lot of other tools in terms of space, it is not always applicable, but it does work on a lot of cases tho.

A lot of situations demand you hold stuff tight, specially if you have a semi-small car and have to move stuff, this is to hold your trunk.

Tire gauge, check your tires always before any medium to long trip.

May not work on oil and stuff like that, but you never know when you might have to touch something nasty and not have a bathroom nearby.

Always have these around, come in handy for spills, drying your hands, etc...

Having one of these in rainy seasons is always good, having a second to carry around is extra convenient.

Multi-purpose towel, From wikipedia.org: "To sit, lie and stand on, to avoid direct contact with the ground, rock, chair, etc. This may be for hygiene and comfort, and in saunas or other places where nudity is common. ... A towel can act as a make-shift garment or blanket."

In case of emergencies don't yell, use these, they are often louder and require less effort than yelling.