Perhaps in the fanfiction, Chloe gets the Miraculous and has to team up with characters she doesn't usually get along with. This could lead to some really interesting character development as she learns to work with others and see their good sides.
One possible plot could be Chloe's journey of self - discovery with the Miraculous. Maybe she starts off using it for the wrong reasons, like for personal gain or to show off, but then realizes the true power is in helping others.
Another plot could be that Chloe gets the Miraculous and discovers a new threat to Paris that the other heroes haven't noticed yet. She then has to use her unique perspective and the power of the Miraculous to save the day, all while trying to prove to herself and others that she can be a true hero.
It could be a new villain created specifically for the fanfiction. Maybe someone who has a vendetta against Chloe and targets her because she has the Miraculous.
One idea could be Chloe's redemption arc in a fanfic. Maybe she starts to realize the error of her ways after a particularly harsh event. For example, she could lose her status among her peers and have to start from scratch to earn their respect. Another plot could be Chloe getting a new Miraculous and learning what it really means to be a hero. She might struggle at first with the responsibilities but grow into a great hero over time.
Well, one interesting plot could be about Ladybug and Chat Noir having to face a villain who can manipulate time. This would put their skills and relationship to the test as they try to outwit the baddie and protect Paris. Another plot might involve a new Miraculous holder emerging and how they interact with Ladybug and Chat Noir, whether it's as an ally or a potential adversary.
One interesting plot could be an alternate universe where Ladybug and Chat Noir have different powers. Maybe Ladybug has the power of ice instead of her usual creation abilities. Another plot could be a time - travel story where they go back to the very beginning of Hawk Moth's reign and try to stop him before he becomes too powerful. And there could also be a story where Ladybug and Chat Noir have to team up with their civilian selves to solve a mystery.
Well, one interesting plot could be the everyday interactions between Marinette and Adrien in a more fluff - centered way. For example, them having a picnic in the park and just sharing cute, innocent conversations. Another plot might be about the kwamis getting involved in the human's daily fluff moments, like Tikki helping Marinette bake cookies for Adrien in a really sweet and clumsy way. And there could also be a plot where the two heroes, Ladybug and Chat Noir, have a non - superhero related date, just enjoying each other's company without the threat of akumas.
One interesting plot could be their adjustment to married life while still dealing with the supernatural elements in Lucifer's world. For example, how they handle his devilish powers and the reactions of those around them.
Another storyline could be set in an alternate universe where Adrien and Chloe are actually siblings. This would completely change their dynamic, and they would have to navigate their new relationship while still dealing with the akuma attacks and the secrets of the Miraculous.
In some fanfictions, there could be a plot where the masks play a role in a time - travel scenario. Maybe Ladybug and Chat Noir find a mask that sends them back in time to the origin of the Miraculous. They then have to make sure not to change history while also learning something crucial about their powers. Also, a plot could be about a mask - making competition in Paris where the villain tries to use it as a cover to steal the Miraculous.
One interesting plot could be the robots in Paris going haywire and Ladybug and Chat Noir having to figure out a new way to fight them since their usual powers might not be as effective. Maybe the robots are being controlled by a new villain who uses technology in a way the heroes haven't seen before.
A really cool plot could be that an international fashion competition is held in Paris and Marinette enters with her Miraculous - themed designs from the boutique. But Hawk Moth tries to use this event to steal the Miraculous. So, the other characters have to not only support Marinette in the competition but also protect the Miraculous at the same time.