One thing missing from most every list I have read of late is a good, multi caliber gun cleaning kit. I had one of those moments not so long ago, and went and purchased one right away to put in that special box. 15 bucks at walmart will get a kit that will clean .17 to 12 gauge, then get some nitro solvent and oil for a couple more.
Hmmm. a weapon that trumps a rifle. I am a fan of the rifle, but this depends heavily on the scenario - if I were stranded on an island and could only have one thing, it would be a *good* knife. Can’t clean game with a firearm, can kill it with a knife (or trap made with the help of a knife...).
A knife can quietly get a rifle, sometimes, when one is needed.