Another interesting aspect could be focusing on a particular character's journey in this anarchy - like Pinkie Pie. How would her normally carefree and fun - loving nature be affected? Maybe she'd try to bring some form of order through her parties in a world that doesn't want it.
Next, focus on your characters. Consider how they will react to the new situation. You might want to pick a main character whose perspective will guide the story. For example, Twilight Sparkle could be a great choice as she's often at the center of important events in the show. She might initially be horrified by the chaos and try to restore order using her knowledge of magic and friendship.
One great 'Gay Sons of Anarchy' fanfic is 'Love on the Road'. It focuses on a relationship between two characters in the Sons of Anarchy world that is really well - developed. The author does a great job of fitting the story into the existing universe.
There might be an anarchy fanfic that focuses on a post - apocalyptic world where there is no central authority. Characters have to form their own rules and communities. For example, a story could revolve around a group of survivors who struggle to maintain order among themselves while also fending off other lawless groups.
I'm not sure if it's extremely popular. There are so many MLP fanfics out there that it's hard to say for certain. It might have a niche following among those who are interested in unique or off - beat interpretations of the MLP world.
Next, focus on the development of the gay relationship. It should be believable and not just forced into the story. Show the characters' emotions, like their fears of acceptance within the biker gang. Maybe one character is afraid of being shunned by his brothers because of his sexuality.
One main theme is loyalty. Whether it's the loyalty within the 'Sons of Anarchy' group in the crossover or the loyalty of characters from the other show. For example, when crossed with 'Game of Thrones', the loyalty to one's club or family in 'Sons of Anarchy' can be compared to the loyalty to one's house in 'Game of Thrones'.
The combination of the concept of anarchy and the popular One Direction makes it interesting. It's like seeing our beloved boy band in a completely different and often wild scenario.
Well, one interesting plot could be about the characters facing a series of unexpected challenges within the stormy setting. Maybe they have to find a way to survive against the powerful forces of nature.