In a steampunk reimagining of the universe, Twilight Sparkle finds perhaps the one pony as lonely as she is. It's rather unfortunate that they're on the moon.
Following the events of Equestrian Equation, Twilight must lead her people to a new life in the Milky Way Galaxy, prevent the established races from exploiting the Herd, and prepare for the inevitable return of the Reapers. (An Interactive story)
No humans. In Equestria's past, ponies exist only to serve their creators. One such pony is accidentally released from her mental chains, but how can one mare save herself and her people if she doesn't even know she's a slave?
The Reapers are invading Equestria, intent upon destroying and enslaving the upstart ponies before they can affect the rest of the cycle. Unfortunately for them, Luna stands in their way.
A Reaper dreadnaught confronts Celestia, intent upon indoctrinating the leadership of the ponies. Said Reaper quickly learns exactly why Celestia has earned the title Unconquered.
Humanity's space exploration ultimately took the form of billions of identical probes, capable of building anything (including astronauts themselves) upon arrival at their destinations. One lands in Equestria. Things go downhill from there.
Luna discovers a vast and ancient being approaching Equus. When she and Celestia go to meet it, they see into the early dawn and eternal twilight of their universe.