Story Topics that, maybe, would be good.

Stories of the Old World: Roam, Gaul, Brittania, Albion, Germania, Persia, etc. Stories are held during the time of the Roman Empires expansion. It could be a pre-dating Celestia story, with maybe her father or ancestor, or Celestia is the Emperor of the Empire.
Point of views from citizens of Rome to that of the Celtic clans/tribes of Brittania. Germania may be good though for a storyline thing though

Annihilation-Human or Equestrian (Evolutionized species meet from the old to new) Could be good? Maybe?

Ancient Beings reawakend from a deep sleep or freed from imprisonment- could become evil or good.

Warhammer or Warhammer 40k story genres- Heretics, Cultists, Spacemarines, Imperial Guard, Missionary, Regular Citizen of Imperium, etc.
Maybe one with a Thousands Son Chaos Space Marine. Hmm.

Any Ideas that anyone could give for a good story topic or idea would be much appreciated.