By no means complete or comprehensive...
A New Messiah. A new Persian Empire. Addictive Entertainment. Advanced Technology disaster. Airplane crash. Anarchy. Antibiotic resistant bacteria. Armageddon. Automotive accident. Avalanche. Aztlan or Reconquista Uprising.
Bank closure or failure, or mandated bank holiday. Becoming a refugee. Becoming lost in the megalopolis. Becoming lost in the wilderness. Biblical flood. Biblical plagues. Black hole appearance. Blackout. Blizzard. Brownout.
Celestial object impact or near miss. Chemical/Biological war or attack. Civil war. Coronal Mass Ejection. Communication restrictions. Crime wave. Crop failures.
Dam failure or collapse. Dangerous wildlife confrontation. Dark matter or anti-matter incident. Drought. Dust bowl.
Earth Core Cooling. Earth orbit shift. Earthquake. Eco-system collapse. Electro Magnetic Pulse. Electro Magnetic Pulse from solar activity. Environmental disaster. Epidemic. Ethnic war. Evidence of extraterrestrials. Extraterrestrial biological contamination.
Fire storm. Flood. Food shortages or price increases. Forest fire/wild fire. Fuel shortages or price increases.
Gamma ray burst from neutron star collision. Global cooling or Ice Age. Global nuclear war. Global warming. Gold or precious metal recall. Gold or precious metal restrictions. Government Tyranny. Grand Alignment induced tectonic activity. Gulf Stream shutdown.
Hail. Hazmat incident. Heat wave. Hostile extraterrestrials. House or apartment or building fire. Hurricane. Hypercane.
Ice Storm. Infrastructure collapse or failures. Invasion of the U.S..
Lahar. Landslide or mudslide. Large scale JIT delivery failures. Limited nuclear war or attack. Limnic eruption. Local major accident involving aircraft, auto, rail or building. Local major crime. Local or regional gun grab. Loss of job.
Magnetic pole shift. Major conventional war. Major economic depression. Major nuclear power plant incident. Martial Law. Massive tectonic activity. Medical emergency. Mega Tsunami - La Palma, West Antarctic Ice Sheet. Mega Volcano - Yellowstone Caldera. Methane Hydrate release.
National bankruptcy or default. Nationwide or global economic breakdown. Nemesis induced Oort Cloud meteorite rain. New colonial activity - France, Spain, Portugal, Italy, Germany, Japan, China, Russia, UK, Brazil, Venezuela, etc.. New, more restrictive assault weapons ban. New World Order.
Out of control bio-genetics or bio-technology or Nano-technology or robotics. Overpopulation. Ozone layer depletion.
Pandemic. Peaceful extraterrestrials. Peak oil. Personal financial breakdown. Personal or family catastrophic illness. Pestilence. Pyroclastic flow.
Racial war. Rainforest deforestation. Rampant inflation. Rapid population decline. Refugees. Regional climate change. Released or escaped dangerous zoo animals. Religious war. Resource war. Rogue military activity. Rotational pole shift. Runaway genetically-modified food plant failure or cross contamination.
Sand or dust storms, or haboob. Sea level drop. Sea level rise. The Second Coming. Severe lightning. Shipwrecked or marooned. Shortages of goods and services for a variety of reasons. Sinkholes. Social breakdown. Solar radiation increase or decrease. State bankruptcy or default. Strikes or boycotts or embargoes or price controls. Sub-atomic particle research accident. Superstorm.
Tailings pond failure or collapse. Terrorism in about a thousand different forms. The Anti-Christ. Tornado. Total gun ban. Train wreck. Travel restrictions. Tsunami.
United Nations or One World Government. U.S. coup. U.S. revolution. Utilities failures.
Vehicle breakdown. Volcano.
Water shortages. Weapons restrictions. Weather Modification attack. When all the furnaces explode. When all the furnaces explode, again. Widespread civil unrest or riots. Wild animal rampage.
Please excuse any redundancies in the list above, of which there are quite a few. Likewise with other errors. The above is not my own -- I didn't compile it, and made only slight alterations.
But relatedly, there's this by Giovanni Tiso over at his Bat, Bean, Beam blog, which has been the home of some favorite reading lately. Worth checking in on, in case you weren't already familiar.