Hunting essentials I never think about?

Over the years, I've gotten a pretty good idea of what I need to be prepared. We all know about the 10 essentials, duct tape, and the basics of hunting/camping gear. But, there are things that some people have thought to use/bring that improve safety, success, or convenience that I've never thought about. I'd imagine I have some things that might make your trips better, too.

So, I'd like to know what "essential" piece of gear you bring along, but others don't. Here's mine:

Hunting:

A small square of tarp to keep your butt dry when sitting

a head lamp

For guns/gunsmithing:

A carpet hall runner with rubber backing. This protects the gun and table while preventing things from rolling.

For camping:

a tea kettle is easier and safer for boiling and dispensing water. It also serves double duty when rinsing dishes.

For the car:

a battery booster pack for when the car dies in the woods when you are alone.

A small trashcan to keep the wilderness tidy.

Hose clamps to reattach loose hoses.