It could be that in an alternate universe, Ash is born as a much older person and becomes May's mother in a more traditional sense. He might have different Pokemon knowledge and experiences which he passes on to May. He could be strict about some things like safety during Pokemon battles and lenient about others, like letting May choose her own first Pokemon even if it's not the most common or powerful choice.
One possible plotline could be that Ash is betrayed by his friends. This heartbreak and sense of abandonment turns him evil. He then starts using his Pokémon in cruel ways to seek revenge on those who wronged him.
One possible plotline could be Ash discovers his latent Aura Guardian abilities gradually. He might start having strange visions or experiences related to aura. Then, he has to find someone to train him, like an old Aura Guardian who has been in hiding.
May would probably look up to Ash even more. Since Ash has a lot of Pokemon - related knowledge and experience, as her'mom', he could pass on some unique skills and wisdom. Their relationship might also have some emotional depth added to it, like when May is feeling down, Ash would be there to comfort her like a mother would, which is different from their usual trainer - to - trainer relationship.
One possible plotline could be that Ash discovers May has been secretly working with a rival trainer in order to gain an advantage in a big tournament. This would make Ash feel betrayed as he thought they were friends and training partners. Another could be that May betrays Ash for a rare Pokémon that Ash was also after, choosing the Pokémon over their friendship.
One possible plotline could be Percy's journey of grief and how he copes with the loss. He might become more withdrawn at first, then gradually find strength in his friends and his quest. Another could be his search for a way to bring his mom back, perhaps delving into dangerous magic or making deals with powerful beings. Maybe he also has to face the fact that his mom's death was part of a larger plan by the villains and he has to stop them from achieving their ultimate goal.
In this fanfiction, a plotline could involve Harry being magically bound to Draco's mom in some way. As a result, he has to stay close to Draco to protect the bond. This could lead to many comical and tense situations between Harry and Draco as they navigate their new relationship. Another possibility is that Draco's mom has left behind a powerful artifact, and Harry is the only one who can find it. Draco, thinking Harry has ulterior motives, tries to stop him at first but then realizes they need to work together. Also, there could be a plotline where Harry accidentally uses a spell that links his mind to Draco's mom, and he has to figure out how to break the link while dealing with Draco's reactions.
A plotline could involve Hermione being magically influenced by a charm that is meant to be a joke but goes wrong. As she becomes more like a 'bimbo', she starts to interact with her friends in different ways. Ron might be initially confused and Harry could be worried. But as the story progresses, Hermione uses her new - found different perspective to solve a mystery in Hogwarts that no one else could because she looks at things from an unexpected angle.
One possible plotline could be that Harry discovers a hidden pirate ship in the Forbidden Forest. He then decides to join the crew and learns the ways of piracy. Another could be that he is magically transported to a pirate world and has to adapt to survive as a pirate.
One possible plotline could be that Naruto discovers a hidden jutsu or artifact that grants him immortality. He then has to deal with the consequences of living forever, like seeing his friends and loved ones age and die while he remains the same. Another could be that an enemy tries to steal his immortality, leading to a great battle.
One possible plotline could be Izuku adjusting to her new gender identity while still trying to pursue her dream of being a hero. She might face different challenges and prejudices in a male - dominated hero world as a girl. For example, some male characters might underestimate her at first but she proves them wrong with her skills and determination.