Just a rough draft. Nothing special.
1. Asteroid Impact
2. Gamma Ray Burst
3. Global Epidemic
4. Rogue Artificial Intelligence
5. Mass Insanity
6. Alien Invasion
7. Mass Infertility
8. ‘Strangelets’ – If the strange matter hypothesis is correct and its surface tension is larger than the aforementioned critical value, then a larger strangelet would be more stable than a smaller one. One speculation that has resulted from the idea is that a strangelet coming into contact with a lump of ordinary matter could convert the ordinary matter to strange matter. This disaster scenario is as follows: one strangelet hits a nucleus, catalyzing its immediate conversion to strange matter. This liberates energy, producing a larger, more stable strangelet, which in turn hits another nucleus, catalyzing its conversion to strange matter. In the end, all the nuclei of all the atoms of Earth are converted, and Earth is reduced to a hot, large lump of strange matter.
9. Technology – humans turning into posthumans.
10. Vacuum Metastability Event – In layman terms, if our universe is indeed made up of what is called a ‘false vacuum’, then it means that our universe is made up of an energy level far too low to be considered stable in any way. If this is the case, our universe could suddenly, without warning, quite simply give up. Our entire universe would shift into a new one with wildly different energy levels, we’d all be wiped out, all the planets, stars, galaxies and everything! Basically the worst thing that ever happen.