First-- If you got "exacto" blades in your kit how are you going to utilize them?
How about an aluminum exacto handle cut down to about 3 inches or so?
Next--Military trip wire is very strong yet flexible and is what they taught us to use for snares in survival schools. And it works.
Now, if you got monofilament fishing line in your kit, have you tried to "unwind" it yet? Having been an avid fisherman all my life I would suggest Braided Dacron. Strong, no memory when you unwind it and can be used for other stuff.
Also, if you got a "fishing kit" in your gear, how about some bait? Berkley makes a large selection of artificial smelly soft plastics. Even a bigger bait can be cut down to smaller portions. But, these MUST be kept in a worm proof air tight container. The oils can melt a lot of plkastics and they can smell up your kit, too.
Again, if you just have to have those lead sinkers, that's personal preferance. But, I can catch just as many if not more fish without sinkers.
Oh, how about a pair of those little scissors you get in a first aid kit? Great for cutting that snare wire.
My personal favorite, a saw blade. 6 inch reciprocating saw blade, fast cutting, and the tip has been sharpened to be used as a spear. About 7 of the bottom teeth are ground away and in that section the outer casing of para cord is wrapped to form somewhat of a handle. You use the saw to cut about a 3/4 in limb, then you saw a "split" in the end to accept the blade, then use the para cord to wrap the blade tighly like primitive spears or arrows. A short handle makes a great saw and several feet make a good spear for fish or whatever looks appetizing. Make the blade however long or short you like.
Well, anyway, those are a few ideas I've had. Thanks for reading.