Another interesting plot could be that there's an ancient vampire curse in Gravity Falls, and Dipper gets caught up in it. He has to find a way to break the curse before it's too late, and in the process, he discovers more about the history of the town and its connection to vampires. This could involve teaming up with Mabel and other characters from the show to solve the mystery.
One idea could be that Female Dipper discovers a way to enter Bill's dimension. There, she tries to understand his chaotic nature. Maybe she finds a side of Bill that's not entirely evil and they form an unlikely bond. For example, Bill could be facing some sort of threat in his own dimension that only Dipper, with her unique human perspective, can help with.
One idea could be a story where baby Dipper and Mabel discover a magical creature in the woods near their home in Gravity Falls. The creature is lost and they decide to help it find its way back. Another could be a fanfic about their first day at daycare in Gravity Falls and all the strange things that happen there. Maybe they meet other kids with unique abilities or find a secret part of the daycare.
One idea could be that Dipper discovers an old journal entry that seems to predict a strange adventure involving him and Wendy. Maybe it leads them to a hidden part of the forest where they have to solve a series of puzzles to get out. Another plot could be that Wendy's friends play a prank on Dipper that goes too far, and Wendy has to make it up to him by going on a quest with him. For example, they could be looking for a mythical creature that Dipper believes exists.
Maybe the fanfic could start with Mabel finding a lemon - shaped amulet. When Dipper touches it, they get transported to a parallel Gravity Falls where everything is lemon - themed. They have to find a way back while dealing with the wacky versions of the townspeople. This would allow for a lot of creative scenarios and character interactions.
A good plot could be set during a time when Dipper has to leave Gravity Falls. Wendy doesn't want him to go without knowing how she really feels, so she kisses him goodbye. Or it could be a plot where they're both investigating a mystery together and find themselves in a tight spot. In that moment of closeness and shared danger, they kiss. Another idea is that Wendy is having a bad day and Dipper tries to cheer her up. As he does, she sees him in a new light and kisses him. Fanfictions often play with the characters' emotions and the unique setting of Gravity Falls to create interesting plots around their relationship.
One plot idea could be that the characters from Gravity Falls enter the Pokemon world. They could go on a journey to become Pokemon trainers, facing challenges like gym battles and Team Rocket - like villains. For example, Dipper and Mabel could each catch their favorite Pokemon and compete in Pokemon contests.
One idea could be that the characters from Reverse Falls accidentally cross over into the Gravity Falls universe. They might initially be seen as threats by the Gravity Falls gang, but then they realize they have to work together to solve a mystery that threatens both universes. For example, a powerful and ancient evil that can only be defeated if they combine their unique skills and knowledge.
Well, in some 'Baby Dipper' fanfictions, he might be the center of a story where the other characters have to protect him from the various threats in Gravity Falls. Since he's a baby, he's more vulnerable. Some fanfictions could also explore how Baby Dipper's presence affects the balance of the town. For example, his innocent nature might draw out different reactions from the usually spooky elements. There are also those that might show his growth in a really short time, like learning to talk and walk really fast because of the strange nature of Gravity Falls.
One interesting Gravity Falls Dark Dipper fanfiction could be one where Dark Dipper is on a quest to uncover a long - forgotten mystery in Gravity Falls. It might involve him using his dark powers in unexpected ways. Another could be a story where he teams up with an unlikely character, like a friendly monster, and they have to face a common enemy.
One idea could be that the characters from Gravity Falls end up in the FNAF world. Dipper might be intrigued by the mystery of the haunted animatronics and try to solve it using his journal. Mabel could befriend the more friendly - looking animatronics, like Chica, and try to make them cute accessories. Another plot could involve the FNAF villains getting loose in Gravity Falls and the Pines family having to use the town's unique magic to stop them.