I have been writing on FimFiction for over a year now, and have several hundred thousand words of published stories, some set in the Conversion Bureau universe.
Dafaddah's Box of Chocolates (compendium of short bits, lyrics, contest entries, etc.)
Filial (A story about Spike, Twilight, Trixie and sea-ponies)
The Vacation Crew (Luna takes a vacation with the mane six)
The Good of the Many (Humans and Equestrians work together to avoid a disaster that could end both worlds - stars the LHC at CERN!)
The Conversion Bureau universe(s):
The Fall of Icarus (A slice-of-life tragedy)
A Newfoal Nöel (Orphan newfoals have a hard time adjusting to Equestria)
Attack of the Killer Muffins! (Parody, with some collab)
Mankind Triumphant - Relic (A dark story of possible insanity and redemption?)
Renaissance Pony (Humanity's influence in the development of pre-classical Equestria)
This last story is still under way and I would much appreciate any advice on it, as it goes heavily into the history of Equestria, covers the period from just before the Hearth's Warming Eve era up to Luna's rebellion, and the main character is none other than Starswirl the Bearded, who (author makes a shameless grab for attention!) started life as Leonardo da Vinci.