A common theme is growth. Since they are teenagers, it often shows how Mabel and Dipper are growing up, facing new challenges, and becoming more mature.
Family is also a significant theme. Their bond as siblings is further explored, like how they support each other through the typical teenage problems. There could be times when they have disagreements but still come back together because of their strong family tie. And of course, the idea of home and what it means to them as they are growing up can be part of it too.
There's 'Mabel and Dipper: Teenage Years of Wonder'. This fan fiction delves into how they handle high school while still having the occasional supernatural encounter. It's really interesting to see how their relationship as siblings evolves in this new setting.
One common theme could be the exploration of a different kind of relationship between them, perhaps in an alternate universe where the normal sibling boundaries are a bit more blurred. Another theme might be the idea of a first kiss and the emotions that come with it.
One common theme is friendship. Even though it's a love game, their strong bond as siblings and friends is often explored. Another theme is mystery, as the nature of the love game itself is usually a mystery they have to solve.
One common theme is sibling adventures. Since Dipper and Mabel are siblings, a lot of fanfictions explore their relationship further while they go on different adventures in Gravity Falls. Another theme is mystery - solving. It's in line with the overall tone of the show, so fanfic writers often create new mysteries for the twins to solve.
A common theme is friendship. Despite their differences, they learn to be friends. Another theme could be growth. For instance, Pacifica may grow to be more accepting of Dipper and Mabel's wacky ways, and Dipper and Mabel may grow in understanding of Pacifica's background.
One common theme could be the theme of responsibility. If we consider the 'pregnancy' as a symbol, it could be about Dipper and Mabel learning to be more responsible for their actions or for something new in their lives, like taking care of a new pet or a new magical item in Gravity Falls.
In Sabrina the Teenage Witch fan fiction, magic is an omnipresent theme. Writers love to create new spells, magical creatures, and magical realms for Sabrina to explore. Another theme is identity. Sabrina has to juggle her mortal and witch identities, and fan fictions often play with this concept. Also, the theme of adventure is quite common. Sabrina goes on all sorts of adventures, whether it's in her hometown of Greendale or in far - off magical lands, and these adventures are a big part of many fan fictions.
One possible theme could be exploring the darker side of sibling relationships. Maybe it delves into how misunderstandings or power imbalances within a family can lead to such a disturbing situation. However, this is a rather unorthodox and potentially disturbing concept for a fanfiction.
One main theme is friendship. Despite the new environment of college, Dipper and Mabel's strong friendship endures and is often a central focus. Another theme is growth. They are growing up and learning to deal with more adult - like situations in college.
Adventure themes are great. For example, they could go on a new mystery - solving adventure in Gravity Falls that the show didn't cover. They could encounter new strange creatures and solve puzzles together.