This is just another reminder to always have emergency funds in your bank account, not tied into the markets. Allows you to weather the storm, until things correct themselves.
Market slowdown, you'll want your bonds.
Recession, you'll want your cash.
Depression, you'll want gold and barterable goods.
Economic collapse or apocalypse, you'll want food, medicine, and alcohol (possibly the most barterable good, also delicious).
In any case anybody reading this in a major city faces non zero likelihood of disaster (take your pick for your city, hurricane, earthquake, tornado, terrorist attack, war) and should be stockpiling 3 liters of water per person in the house per day you want to be able to survive on your own, alongside 2k calories of food, trash bags, etc. I say have a stocked liquor cabinet as well because my experience in Backcountry many week hikes has taught me you can get nearly anything in return for good liquor :)
I've also heard strong arguments for the stockpiling of pornography and certain chemicals that are valuable in tbe production of medicine or just used as general reagents, don't know too much about chemical stockpiling though.
Careful for the prepper rabbit hole, it runs so very deep ;)
Potassium permanganate - A swiss army knife of a chemical. It can be used to clean certain contaminants from water, clean wounds, start fires, and it's cheap as dirt.
Aqua Regia - A mixture of muriatic acid and nitric acid. I can imagine this being useful to smuggle gold through bandit warlord checkpoints. George de Hevesy dissolved a nobel prize medal to hide it from nazis. Acids in general are useful.
Sulfur - Depending on your location, this is the hardest component to obtain for making gunpowder. The other components can be made from pee and cooked wood.
That's all I can think of off the top of my head. Note: I am neither a chemist nor a prepper.
However after this winter's experience where two feet of snow ran the supermarkets out of fresh food, I'm going to keep slightly more food and folding money on hand.
But remember these are long-term processes. Ultimately your connections and community will become important in economic collapses, because they're usually very slow-motion.
It analyzes the citizen responses to several catastrophic disasters. Turns out, people don't turn into ravaging wolves in a disaster, they immediately begin to help their neighbor, with no regard to race color Creed etc. It's when the national guard comes in that issues start arising...
Also:
Potassium iodide in case of nuclear fallout ($9 for 2-week supply)
Chlorine dioxide for water purification ($10 for 1-week supply)
Both are pretty shelf stable (4-6 years) so you don't need to keep buying them.
Tuck away a few hundred bucks in small bills. It will be more valuable than a chest full of gold when you really need it. It suuuuuuuucks to be caught without physical cash in an emergency.