Well, a popular plotline is the exploration of their different powers. Frisk has their unique abilities and Betty has hers. In some fanfictions, they end up teaching each other about their powers. Also, there could be a plot where Frisk and Betty are from different timelines that somehow merge. This creates a lot of tension and also opportunities for their relationship to grow as they navigate this new, chaotic situation.
Writers often start with conflict. Since Betty is usually seen as a bit of a bad girl in Glitchtale, there's an initial tension with Frisk. They might make Frisk be the one to break through Betty's tough exterior. For example, Frisk could save Betty's life in a dangerous situation, which makes Betty start to question her views on Frisk.
One interesting plotline could be a journey of self - discovery for both Chara and Frisk. They might face challenges in the Underground together and through that, their relationship deepens. Another could be a story where they have to overcome misunderstandings. For example, Chara's past actions might be misinterpreted by Frisk at first, but they eventually work it out.
Well, it could be that in this fanfiction, Frisk gets bullied because they come from a different background than the others. The bullies target Frisk for being an outsider. As the story progresses, Frisk could meet a mentor - like character who helps them gain confidence and teaches them how to deal with the bullies. Frisk might then use kindness and understanding to turn the situation around and make the bullies realize their mistakes.
One popular theme is friendship. They might explore how Frisk and Chara form a strong bond in different scenarios. Another is adventure, where they go on quests together in the Underground world. Redemption is also a theme, like Chara getting a chance to be redeemed through her relationship with Frisk.
One reason could be the popularity of the Undertale characters Frisk and Sans themselves. Fans love these characters and are eager to see different interpretations of their relationship. The 'flowerfell' concept also adds an interesting twist. It makes the stories more unique compared to regular Undertale fanfictions.
High - school drama is also common. They might write about school events, popularity contests, and how these affect the relationships of the three characters. For example, a story could be about how a school dance creates more tension in the love triangle.
One possible plotline could be a love triangle where the reader is caught between Frisk's kindness and Chara's more complex nature. Maybe the reader meets Frisk first, and they have a sweet, innocent relationship. But then Chara enters the picture, bringing a sense of mystery and a different kind of charm. The story could revolve around the reader's internal struggle to choose between them, with different adventures and emotional moments along the way.
Ink!Sans is a popular pick. His creative and somewhat unpredictable nature can bring a lot of color (literally and figuratively) to a Glitchtale crossover. He could use his paint powers in the Glitchtale world in ways that no one expects. Also, Bete Noire from Glitchtale is a character that many fans like to include. Her relationship with other characters, especially her sister, can be explored in new and interesting ways when in a crossover situation.
One common plotline is them working together to save the Underground. They combine their unique abilities and perspectives to find solutions to the problems that the Underground is facing, like the threat from the monsters or some sort of environmental disaster within the Underground world.
Another plotline could be a 'reunion kiss'. Maybe they had a fight or were separated for some reason, and when they see each other again, the passion is overwhelming. In some fanfictions, this could be set in a context where Jughead has been away for a while, and when he returns, he can't resist kissing Betty. This often leads to a rekindling of their relationship and more adventures together.