One possible plotline could be Twilight turning evil due to a dark magic spell gone wrong. She might start to oppose her friends and try to take over Equestria with her newfound dark powers.
One possible plotline could be that Twilight is influenced by a powerful dark magic artifact. Maybe she discovers an ancient book that slowly corrupts her mind, making her turn against her friends. As she turns evil, she might start to use her powerful magic to take over Ponyville, believing that she can create a 'better' world under her rule.
In some fanfictions, Trixie might initially be up to her old tricks of showing off, but then she and Twilight get into a situation where they have to rely on each other. For example, they could be trapped in an enchanted forest and have to work together to find their way out. Trixie could use her showmanship skills to distract dangerous creatures while Twilight uses her book - smart magic to find the exit.
Obviously, her closest friends like Rainbow Dash, Pinkie Pie, and Rarity would be the main ones affected. Rainbow Dash might try to oppose Twilight's evil ways directly, leading to some intense aerial battles. Pinkie Pie's usual cheerfulness could be crushed as she tries to figure out what went wrong with Twilight.
Well, a great plotline might be a werewolf pony that was once a normal pony but got cursed. This pony then has to find a way to break the curse while dealing with the prejudice from other ponies who are scared of werewolves. Or perhaps a story where a werewolf pony falls in love with a regular pony, and they have to overcome the obstacles of their different natures and the disapproval of the pony community.
Well, a great 'My Little Pony Twilight Fanfiction' might be one where Twilight is faced with a mysterious force that is draining the magic from Equestria. She has to use her intelligence and all the knowledge she has gathered to find the source and stop it. Some fanfictions also explore Twilight's role as a princess in different scenarios. For example, she could be in charge of organizing a grand magical event across all of Equestria and has to deal with various problems and challenges along the way.
One common plotline is about Twilight dealing with the challenges of her pregnancy while still trying to fulfill her duties in Ponyville. Another could be how her friends support her during this time. Maybe there are also plotlines where she discovers something special about her unborn foal, like it has some unique magic abilities.
Well, some plotlines might involve the ponies' adventures related to the secrets in Ponyville. For example, they might go on a quest to find the origin of a mysterious secret that has been passed down for generations. It could also be about how a new pony in town accidentally stumbles upon a secret club in Ponyville and has to prove herself worthy to be part of it or keep the secret safe.
Well, sometimes there are plotlines where ponies from different generations of My Little Pony enter the death battle. For example, the classic ponies from the old series might face off against the modern ones. This can lead to some really cool comparisons of their powers, looks, and personalities. Also, there could be a plotline where a pony has to fight an evil version of itself, which is always a great source of internal conflict.
One interesting plot could be Twilight and Fluttershy going on an adventure together to discover a new type of magic in Equestria. They might face challenges along the way that test their friendship and their individual skills.
One interesting aspect could be the exploration of a darker side of Twilight. It might show her facing more complex and morally ambiguous situations that are different from the usual light - hearted stories in the regular My Little Pony series. This can add depth to her character.