The next source may be a long way off. This, too, is gear you do not expect to use. A polypropylene or wool sweater is fine. Even better is a small Mylar space blanket, the kind that comes folded up in a little cellophane package about 2 inches by 4 inches. These are extremely compact, weigh practically nothing, and can be tucked into your emergency kit and forgotten until needed.
Garbage bags make good rain and wind protection.
They can also be used for gathering food, insulating, as fire-making material, for forming part of a shelter, or for melting snow. A topographic map is essential for any wilderness navigation. It also can be tucked inside your clothes for insulation or used to leave notes or directions addressed to potential rescuers. Be sure you know how to use both a map and compass or they won't do you much good. If your compass is the type with a mirror, it can double as a signaling device.