A really interesting Young Bruce Wayne and Alfred fanfiction storyline could be one where Alfred has a secret past as a spy. This could add a whole new layer to their relationship as he teaches Bruce some of his spy skills. It would be exciting to see Bruce adapt these skills in his crime - fighting later on.
There could also be a fanfiction where Bruce Wayne is a child prodigy and Alfred has to deal with his extremely advanced intelligence. This might lead to situations where Bruce is coming up with wild and dangerous plans to fight crime even at a young age, and Alfred has to temper his enthusiasm while still encouraging his natural abilities.
The fanfiction often delves into the emotional connection between the two. Alfred is the one stable presence in Bruce's life. He is there to pick up the pieces when Bruce fails or has a setback. And Bruce, in turn, respects Alfred's wisdom and advice. In some fanfictions, Bruce might confide in Alfred things he wouldn't tell anyone else, like his doubts about whether he can really make a difference in Gotham. This shows the deep trust between them.
Another aspect could be that in some darker fanfics, if Bruce Wayne were to cross a moral line, perhaps Alfred would have to take more extreme measures. He might cut off Bruce's financial resources related to his vigilante activities. This would force Bruce to re - evaluate his actions and the way he operates as Batman. It's a way of punishing him to make him understand the importance of ethics even in his fight against crime.
Believable young Bruce Wayne is about showing his evolution. Start with his basic characteristics. He's smart, already showing signs of being a prodigy. But then add in the emotional aspects. He's angry about what happened to his parents but channels that anger into something positive. He might start small, like helping a neighbor who has been robbed. His relationships with other kids his age are also important. He might not fit in completely because of his different mindset. And his growing obsession with bats could be a unique quirk that you play up, as it ties into his future identity as Batman.
There are also fanfics where Alfred withholds his support for Bruce's Batman activities as a form of punishment. Since Alfred is crucial in maintaining the Batcave, providing technical support, etc., without his help, Bruce would find it much harder to be Batman. This forces Bruce to think about his actions and make amends if he wants to get Alfred's support back.
One storyline could be that Harry, after the events in the wizarding world, decides to take a break and travels to Gotham. There he meets Bruce, and they end up teaming up to take on a new threat that combines magic and Gotham's usual criminal element. Maybe a villain who has somehow gotten hold of a powerful magical artifact and is using it to wreak havoc in the city.
A possible storyline could be that Percy is on a quest and gets lost in a different dimension which happens to be Gotham. Bruce Wayne, as Batman, finds him and initially suspects him to be a threat. But as they interact, they discover some similarities in their abilities and goals. They then start to dig deeper and find out they are related through a long - lost family connection that dates back to ancient times when the gods had some influence on the early human civilizations.
One possible storyline is a competition between them. They could bet on who can solve a particular global threat faster. Bruce would use his detective skills and resources in Gotham, while Tony would rely on his Stark tech. Another could be that they get framed for a crime together and have to work together to clear their names while also finding the real culprit.
Perhaps a story where Bruce Wayne is at the police academy undercover to investigate a series of crimes that seem to be linked to someone in the academy. He has to balance his normal life as Bruce, his training at the academy, and his secret investigation. He could make friends with some cadets who end up helping him in his mission, or he could be in a situation where he has to choose between following the academy rules and doing what he believes is right to solve the case.
One possible storyline could be that Bruce Wayne gets injured during a fight with a new and powerful villain in Gotham. He has to rely on his allies like Alfred and the Bat - family more than ever to keep Gotham safe while he recovers. Another could be that he gets injured in his civilian identity, and has to hide his true nature even more carefully to avoid suspicion as he heals.
Often, she is depicted as being just as intelligent as the male Bruce Wayne. For example, she has a sharp mind for detective work and strategy. She might be able to quickly analyze crime scenes and figure out the motives of the villains.