Were I putting together a 'forever prep', one small thing I can think to add is peppercorns. They are lightweight, easily stored and, in a SHingTF situation, people will still want their food seasoned. Peppercorns used to be valuable as monetary barter exchange for a reason, and there's nothing to indicate that our desire for pepper has lessened. But make sure it's the peppercorns, not preground pepper as that will go stale very quickly. One can also add other cooking 'seeds' as, again, they are light in weight and easily stored. Things like carraway seeds, mustard seeds, coriander seeds, cumin seeds, cinnamon sticks, bay leaves, in fact, just about any spice in a dried whole, not ground, form. Of course, if one is storing such things, you'll need som way to grind it up. Mortar and pestle is the obvious choice, but a hand grinder, preferably made of wood or metal (I have a plastic one and do not think it would survive SHingTF use for very long without breaking) would be good. Just my pennies thrown into the pot.