This group is for stories that take place in the Observations Universe.
The Observations started with Starswirl the Banished, as he delved into the secrets of his world. He believes that he's found a doorway to alternate realities, but before he could finish his experiment, everything he'd cared about had been taken from him.
Now, Twilight Sparkle is in possession of Starswirl's private journal, and with it, access to the secret history of her own world.
Since the timeline jumps around a bit, the following is the chronology of some of the characters.
For Twilight's arc the stories follow this order:
Observations->Motivations->Preservations
Spikes & Whelp's Arc:
Motivations:Relic
Finally, there is Starswirl's Arc->
Motivations->(DDGtE)->Motivations->Motivations:Relic->Observations->Preservations
Aaron's Arc
DDGtE->Throne of Ouroboros