Another thing to add to the list: EMP or other attack on the power grid. I know this sounds a bit tinfoil hat, but it’s really quite serious. I know people on the NERC board who are quite concerned about the grid’s vulnerability to this, and multiple congressional reports outline the risks. I will admit that the assumption that (for e.g.) cars will stop working if there’s an EMP is unproven and subject to dispute, but after living through a few days of disruption to the power grid courtesy of PG&E, I can tell you a few months of disruption would be catastrophic.