One interesting concept could be the exploration of different dimensions, which is often a theme in Gravity Falls. In the 'drifting stars' fanfiction, perhaps the stars are portals to these alternate dimensions. The characters might encounter strange creatures or new forms of magic while traversing through these star - related portals.
Stanley and Stanford Pines might also be important characters. Given their knowledge of the town's secrets and their past experiences, they could play a crucial role in the 'drifting stars' fanfiction. They might have some prior knowledge about the stars or be able to provide some guidance to Dipper and Mabel as they explore the mystery of the drifting stars.
One interesting concept could be the characters from Gravity Falls getting Saiyan powers. For example, Dipper could discover he has latent Saiyan abilities and start training like Goku. This would change his dynamic in the Gravity Falls world as he tries to balance his newfound power with the mysteries of his hometown.
One interesting fanfic could be where the characters go on a magical adventure during a meteor shower. They might discover new secrets about Gravity Falls that are only revealed under the stars.
Perhaps the character interactions are a key concept. Imagine Dipper from Gravity Falls meeting Star from SVTFOE. Dipper's inquisitive nature and Star's bold and impulsive personality could lead to some really fun and unexpected adventures. They might team up to solve a mystery that involves both the Gravity Falls' mystery and the magic of SVTFOE.
One interesting Gravity Falls fanfiction could be those that explore the further adventures of Dipper and Mabel after the events of the show. For example, a story where they discover a new mystery in Gravity Falls during their next summer vacation. Another could be a fanfic that delves into the backstory of Bill Cipher and his connection to other characters in a more detailed way. There are also fanfictions that focus on the relationship between the characters, like how Dipper and Wendy's friendship might develop further.
One interesting storyline could be the characters from both universes teaming up to solve a mystery that spans across their respective worlds. For example, Dipper from Gravity Falls and a character from Relativity Falls might work together to figure out a strange phenomenon that is affecting both places.
One interesting Gravity Falls OC fanfiction could be about an OC who has the power to control time and how they interact with the main characters like Dipper and Mabel. They might use their power to prevent certain disasters in Gravity Falls or to gain knowledge from different time periods.
One idea could be a Gravity Falls and Steven Universe crossover. Dipper and Mabel could meet Steven and the Gems. Maybe they'd team up to solve a mystery that involves both Gravity Falls' strange phenomena and the Gem-related threats. It would be cool to see how the different magical elements interact.
One interesting Gravity Falls supernatural fanfiction could be about Dipper and Mabel encountering a new type of supernatural creature that's not in the original show, like a time - traveling ghost. It could add a whole new layer of mystery and adventure to their summer in Gravity Falls.
One interesting Gravity Falls lemons fanfiction could be the ones that explore different character relationships in a new light. For example, a story might focus on Dipper and Mabel's adventures with a unique twist on their bond, without going into inappropriate territory. Another could be about the mystery - solving aspect but with a touch of character - centric drama. However, it's important to note that fanfiction can vary greatly in quality and adherence to the original spirit of the show.