A great plot for a Wonderess Mirror fanfiction could be a mystery surrounding the mirror. Characters notice strange things happening around it, like objects disappearing or reappearing in different locations. They then embark on a journey to figure out what's going on. It could also involve a villain who wants to use the mirror's power for evil, and the heroes have to stop them.
You could write a story about a person who is transported into the world inside the Wonderess Mirror. In this world, everything is different, and they have to find a way to get back. Along the way, they meet unique characters and face various challenges. This could include solving puzzles that are related to the mirror's properties and learning about the history of the mirror's world.
Perhaps an old wizard could be the main character. He has heard tales of the Wonderess Mirror all his life and finally locates it. He uses his magical knowledge to try and understand the mirror, but realizes there are forces at work that are far beyond his initial understanding. His character could bring a sense of wisdom and experience to the fanfiction.
One idea could be exploring the backstory of a minor character in 'the mirror darkly'. Maybe they have a secret connection to the main mystery that hasn't been revealed yet.
In 'through a mirror darkly fanfiction', a great plot idea might be to introduce a new character who has the power to manipulate the mirror itself. This new character could be either a villain or an ally. If a villain, they could use the mirror to cause chaos and confusion among the existing characters. If an ally, they could help the others understand the true nature of the mirror and use it for good. This would add a whole new layer of intrigue to the story.
One idea could be a trainer getting trapped in the Mirror World and having to find a way back while facing distorted versions of Pokemon. For example, a Pikachu that can use dark - type moves instead of electric ones.
One plot idea could be that in a magical mirror world, Severus Snape encounters Rumplestiltskin. Maybe Snape is seeking a way to reverse a dark spell he accidentally cast, and Rumplestiltskin offers to help in exchange for something precious to Snape, like his memories of Lily. Another could be that the mirror shows an alternate reality where Snape has the power of Rumplestiltskin's deal - making, and he uses it to change the fate of Hogwarts during the war.
One idea could be that the OC has a special power that can counteract the Mirror's dark magic. For example, if the Mirror is trying to manipulate Snow White, the OC's power could be to disrupt the Mirror's illusions. Another plot idea is that the OC has a past connection with the Mirror. Maybe the OC's ancestors were the ones who first trapped the Mirror's dark essence, and now the Mirror wants revenge on the OC. Also, the OC could be a healer who tries to cure the Huntsman of any dark influence the Mirror might have put on him.
Well, in an MLP Dark Mirror Universe fanfic, a possible plot is that the Elements of Harmony are actually used for evil. The ponies who usually protect Equestria are now using the power of the elements to control and oppress others. There could also be a plot where the different pony races are at war with each other instead of living in harmony. Maybe the unicorns think they are superior and are trying to enslave the earth ponies and pegasi. And of course, the fanfic could explore how the friendships that were once strong in the normal Equestria are now broken in this dark mirror world.
One idea could be a Mirror Naruto where he has different elemental affinities. For example, instead of wind, he has lightning as his main element and uses it in unique jutsu combinations. Another could be a Mirror Naruto who was raised in a different village and has different values and goals compared to the original Naruto. He might be more focused on stealth and assassination rather than the open - hearted approach of the real Naruto.
Perhaps Amanda Serak is a double agent in the Mirror Universe. She pretends to be loyal to one faction while secretly working for another. Her mission could be to gather intelligence about a new weapon or technology that could change the power dynamics in the Mirror Universe. As she gets deeper into her mission, she realizes that she may be in over her head and has to make some difficult decisions to protect herself and those she cares about.
One idea could be exploring the unspoken stories of the ranch hands. Maybe there's a hidden love affair between two of them that has to be kept secret due to the social norms of 1923. Another could be focusing on how a young character dreams of leaving the ranch and going to the big city, but faces many obstacles. And a third idea could be a mystery plot where strange things start happening on the ranch and the characters have to figure out what's going on.