One possible plot could be that Naruto is actually an undercover agent for a secret organization and has to fool everyone in the village to keep his cover. So he acts like the goofy Naruto they all know while secretly passing on information.
It could be that Naruto has a new power that he doesn't want anyone to know about yet. So he fools everyone by pretending to be weaker than he actually is. He makes mistakes on purpose during battles and training, all while secretly mastering his new ability in private. This way, when the time is right, he can surprise his enemies and protect his friends more effectively.
Well, it could imply that in this fanfiction, Naruto is somehow deceiving all the other characters. Maybe he has a hidden agenda or is playing a complex game that involves tricking everyone around him.
One possible plot could be Sakura trying to get an autograph from Uxumaki. She might go on a journey to find Uxumaki and face many obstacles along the way.
Perhaps Teddy is an artist who is strangely inspired by skulls. In the fanfiction, Teddy uses skulls as models for his art, but as he delves deeper into this obsession, strange things start to happen around him. He might start seeing visions related to the skulls, and his art takes on a life of its own. It could be a psychological exploration of an artist's mind and his relationship with a rather macabre subject.
One possible plot could be that Ash finds a lost Riolu in a forest. He decides to take it under his wing and train it. Along the way, they face off against a group of poachers who are after Riolu for its rare abilities.
One plot could be that Marinette discovers a new power and with it, she manages to save the day in a really spectacular way. This makes everyone in the story realize how amazing she is and they all start to love and respect her even more.
One possible plot could be that everyone believes false rumors about Harry being a dark wizard. His friends from Hogwarts, including Ron and Hermione, turn their backs on him. Harry then has to find a way to prove his innocence all alone, perhaps by going into hiding and secretly investigating who spread the lies.
Perhaps Ash hates everyone because he has lost too much in his journey. He has seen Pokémon get hurt, friends leave, and goals unachieved. This build - up of disappointments could turn into hatred for all those around him. He might then isolate himself and the fanfiction could be about his journey to either overcome this hatred or succumb to it.
Maybe Naruto resigns because he discovers that there is a conspiracy within the village leadership that he doesn't want to be a part of. He resigns in protest and sets out to expose the truth on his own. His friends are initially shocked but then join him in his quest.
One possible plot could be that Pikachu sacrifices itself to save Ash from a powerful enemy. Ash then has to deal with the grief and also tries to find a way to bring Pikachu back. Another could be that there's a mysterious disease that spreads among Pokemon and Pikachu is one of the victims. This leads to a search for a cure and also a mourning period for the beloved Pokemon.
Perhaps Meredith is being targeted by a rival hospital or a group of disgruntled doctors. Addison, with her connections and wits, creates a shield around Meredith. She could arrange for extra security, or she could use her diplomatic skills to defuse the situation. It could also be that Meredith is having some family - related problems that are affecting her work, and Addison helps her keep it together at the hospital so that her career doesn't suffer.