One item that doesn't have to worry about being left at home is a lightweight folding saw. I've tucked one into my pack for years and it has stayed there because of the regular use I put it to. The saw I have been carrying, has worked, but it's been barely adequate. Recently, a new folding saw arrived for me to check out, and I like it enough that the old one is now retired and living on a shelf.
This new saw is marketed by Bass Pro as part of their RedHead line. It's called The Hunt Folding Saw and features a 6" blade which locks in both the open and the closed positions, as well as a soft rubber handle with lots of hand traction. Those two features make the saw both safe and comfortable to use. Safe is good, because that blade features a double row of crazy sharp teeth which make short work of any reasonably sized limbs or branches. And those teeth are offset enough, that the saw never binds, unless the branch folds back to pinch the blade—which is usually operator error. It's like the designers of this saw, have actually used saws themselves. I've certainly been using it, and so far I've cleared shooting lanes, built a gun rest at a blind and made a skinning pole. Considering the cost is a measly $20 bill, this is great value for a tool so capable.
If you've never tried a good folding saw, consider giving this one a run. Saws are safer to use than a hatchet and lighter to carry. They also require significantly less energy to operate, something which could be important in an emergency, where building a fire or a shelter is a life-saving endeavour. Folding saws are lightweight tools which can contribute regularly to the success and safety of an outing, making them a device capable of earning a place in any hunter's pack. They certainly have one in mine.