Here are some more time periods.
11. The Anunnaki Experience
Visiting apotheoist extraterrestrials cover globe in stone pyramids and elaborate geographs of birds. Local proto-elves are terribly confused, as they had already created stone pyramids and elaborate geographs of birds and were really looking forward to cheap fusion and metamaterials.
12. Gnomic Explosion
A species of gnomes achieves asexual reproduction through budding, floods ecosystem with tiny magical men with pointy hats. Predators forced to convert to gnomovorism or starve. Toadstool cities drive out local flora, widespread psychotropic pollen storms become a regular occurrence.
13. Zaratanic Column
An era of near-total oceanic coverage, marked primarily by a strata consisting primarily the compressed shells of continent-sized turtles. Similar specimens and their endemic parasite-descended civilizations have been found in fewer numbers in multiple subsequent geological periods.
14. Bootleg Epoch
Global biosphere replaced with cheaper, unlicensed biosphere. Flora and fauna of are of low quality and break down regularly. Colors and proportions are askew, incorrect or confusing categorization is commonplace. Era ends after enforcement of new divine copyright laws.
The universe, finally realizing that mistakes have been made, decides to flush itself out and start over. Everyone and everything is miserable except for the cosmic vampires, who are flourishing. Vampires are wiped out by the next generation of starchildren.
16. The Recreation EraA completely accidental mass extinction wipes out all life on the planet save a sapient species of bivalve-descent hominids. Survivors attempt to recreate their destroyed world by putting on elaborate costumes and filling as many niches as possible.
17. Crazy Cat Age
Cats release variant toxoplasmosis strain into atmosphere, assume indirect control of class mammalia. Reign of the God-Felines is eventually overthrown by an alliance between reptilians, insects, and shoof. Shoof driven to extinction during war; nature of the creatures unknown, their sacrifice is not forgotten.
18. The Great Re-Alignment
The stable law-chaos matrix is thrown into disarray as a close encounter with another plane leaves a residue of sub-atomic moralitons smeared across the universe. Thousands of competing ethics gradients emerge and fight for dominance via imprinting upon biological life. Law-chaos matrix eventually re-asserts dominance after collapse of the good-evil matrix into civil war.
19. Terrible Reign of the Sport Kings
Ordinary sporting event featuring utterly mediocre teams results in indefinite extension of overtime. Game continues despite catastrophic nuclear war annihilating parent civilization. Teams and fans eventually diverge into two separate species. Evolutionary arms race devoted to out-competing enemy team. Age is finally drawn to the close as the ultra-umpire appears on the scene, devouring both teams and declaring a mutual forfeit.
20. The Morte Paradox
Thin, unremarkable strata that contains the tombs of every sapient being that is currently alive. Society in turmoil as governments and scientists debate over whether or not the tombs should be opened. Conspiracies and denials abound. Skeletons celebrate, though are not specific about why.