Perhaps there's a new type of paparazzi technology that can take pictures from long distances and through walls. This becomes a huge problem for the Bat Family as they can't seem to escape being photographed. They then have to enlist the help of Lucius Fox to create some kind of counter - technology to block these invasive photos and protect their identities and their operations.
One idea could be that a paparazzo discovers a secret entrance to the Batcave and tries to sell the information. The Bat Family has to race against time to stop him before their identities are fully revealed. Another could be that the paparazzi are being used by a villain to distract the Bat Family from a bigger threat in the city.
Well, it might focus on the comical side. Imagine the paparazzi trying to take pictures of Robin while he's doing his acrobatic stunts and getting all flustered when Robin outsmarts them. Or they could be trying to get a photo of Batgirl on her motorcycle and end up in some really silly situations as she zooms away from them.
One idea could be a story where a new student arrives at the school who is secretly a member of the bat family. They have to balance their normal school life with their superhero duties. For example, they might be late for class because they were out stopping a crime the night before.
One idea could be that the bat family encounters a supernatural force that gives them new powers. For example, they might come across a magical amulet that allows them to fly without their gadgets for a short time.
A third idea is to have a time - travel plot where members of the Bat Family in Young Justice go back in time to a crucial moment in Batman's early days as a vigilante. They could witness events that shaped Batman into the hero he is and learn valuable lessons from it. Along the way, they might also accidentally change something in the past, creating a whole new set of challenges to fix in the present.
One idea could be that the Bat family is investigating a strange series of crimes in Gotham. Meanwhile, the Young Justice team stumbles upon a lead that takes them to Gotham as well. They initially clash due to different methods of operation. Batman tries to keep his family in line while also dealing with the young, headstrong heroes of Young Justice.
A Bat Family OC fanfiction could focus on an OC who is an artist. They use their art as a form of communication and also as a way to leave clues for the Bat Family. This OC might be in the middle of a mystery that involves some of Gotham's art underworld. The Bat Family has to figure out how this OC fits into the bigger picture. It could also be an OC who is a street kid that Batman takes under his wing. This kid has a natural talent for acrobatics and stealth, and slowly becomes an important part of the Bat Family.
One idea could be a crossover where the Bat family teams up with the Teen Titans. They could combine their skills to take on a powerful new villain that neither group could defeat alone. For example, Batman's detective skills and Robin's agility along with the Titans' unique powers would make for an exciting story.
One idea could be exploring the relationship between Batman and Robin in a different light. Maybe Robin has to take on Batman's role temporarily when Batman is injured. Another idea is a story about Batgirl's early days of training and how she overcame difficulties.
One interesting 'bat family moment' in fanfic could be when all the members of the bat family come together for a family dinner. It's a rare occasion as they are often busy with their crime - fighting duties. They share stories, jokes, and there's a sense of normalcy in that moment.
A possible plot is that Thomas Wayne is resurrected and finds the Bat Family. He has to come to terms with how far Bruce has gone in his fight against crime. Maybe he joins the Bat Family temporarily to take on a new and dangerous threat in Gotham. He could also have some interesting interactions with characters like Alfred, sharing stories from the past and giving new insights into the Wayne family history.