There are several addition weapons and support I would like to have:
1) .177 air rifle with several thousand pellets that can be used for small game. Quiet, accurate and effective. You can have thousands of "rounds" in one hand. Air rifles today are significantly more powerful than most realize.
2) x-bow and enough arrows and broadheads
3) compound bow ditto
4) traps for various size animals
The one common denominator I see is to have standard cartridges that allows ability to trade components with others for whatever. 30/30, 30-06, .308 (note all .30 cal). Lead bullet bullets for .30 cal rifle.
Revolver in .357Mag/.38 spl capability. Lead molds for easy component availability. Heck plenty of range brass. Common primers.
A 12 ga is nice but difficult to amass enough ammo.