Perhaps in the fanfiction, Bruce Wayne's girl best friend has a special power or skill, like she can read minds. She accidentally reads Bruce's mind and discovers his Batman identity. She then has to decide whether to keep it a secret or use her power to help him in a more strategic way. This would completely change the dynamics of their friendship and open up a whole new set of adventures for them.
Another storyline could be set during a gala in Gotham. Bruce's girl best friend gets into trouble with some of the seedy characters at the event. Bruce, as Batman, has to save her without revealing his identity to her. This would lead to a lot of internal conflict for Bruce and some interesting interactions between them afterwards.
There could be a fanfiction where Bruce Wayne's girl best friend is from a rival family in Gotham. Despite their families' differences, they form a strong bond. They might have to navigate through the complex web of Gotham's underworld politics while maintaining their friendship. Their relationship could be a source of both comfort and conflict for Bruce as he tries to protect Gotham.
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.
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.
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.
One possible storyline could be exploring the immediate aftermath of Bruce's death. How does Terry McGinnis handle the loss? Another could be flashbacks to Bruce's final days, showing his last words of wisdom to Terry.
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.
Well, there's this fanfiction where a female journalist is trying to uncover the truth about Bruce Wayne and in the process, she falls in love with the man behind the mask. It's really interesting as it shows the contrast between the public image of Bruce and the real him. Then there's a story where a female detective teams up with Bruce Wayne to solve a mystery in Gotham. Their interactions are full of tension and underlying attraction. Also, there's a fanfic that imagines a female martial artist meeting Bruce Wayne and teaching him some new fighting techniques, which changes their relationship dynamic.
One reason could be that Bruce Wayne never had the traumatic event that led him to become Batman in the original story. Maybe his parents' death was prevented somehow, so he never felt the need for vengeance and justice in that extreme way.