Well, there are several out there. Some focus on how Gaster and Grillby meet in unexpected situations. For example, in 'Gaster's Discovery of Grillby's World', Gaster stumbles upon Grillby's place and a whole new set of adventures begin. These fanfictions usually explore their potential for friendship or something more, depending on the writer's take.
You can start by looking on popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of different fanfictions, including those about Gaster and Grillby.
There are many great Grillby x Reader fanfictions. Some might focus on their first encounter in the Underground world. For example, in some stories, the Reader stumbles into Grillby's bar by accident and a unique friendship begins. Another common theme is how Grillby's calm and mysterious nature interacts with the Reader's more adventurous or curious personality. You can find these stories on popular fanfiction platforms like Archive of Our Own.
The war between Gaster and Grillby in the fanfiction might have been sparked by a personal grudge or a competition for influence. Maybe there was a hidden secret that drove them apart and into conflict.
One common theme could be the exploration of their relationship in the context of the outertale universe. It might involve how they interact with the unique settings and other characters in that AU.
There could be some. You might want to check out fanfiction websites like Archive of Our Own. However, the availability and quality can vary. Sometimes it takes some searching through different tags and filters to find the really good ones.
There are also fanfictions that focus on a more emotional aspect of their relationship. Maybe Gaster has some secrets that only Asgore can understand, or vice versa. They might support each other through difficult times, like when Asgore is feeling the pressure of leading the monsters.
There might be a fanfiction where Gaster, with his mysterious past and knowledge, helps Asgore deal with the guilt of past actions. As they spend time together, they discover new sides of each other and a yaoi - themed relationship blossoms. It could involve Gaster showing Asgore different perspectives on leadership and forgiveness.
One reason could be the exploration of new relationships within the established fandom. Fans like to see how these two characters, who have their own identities in the 'underfell' universe, interact in a romantic and often yaoi - themed way. It allows for creativity in storytelling, like how they overcome differences or how their relationship develops in a world full of challenges. Also, the yaoi aspect appeals to those who enjoy male - male relationship stories, adding a new dimension to the existing lore of the 'underfell' world.
One common theme is friendship. Despite their different natures, Sans and Grillby can be shown developing a deep bond. Another theme is the contrast between their personalities. Sans is often more laid - back and Grillby is more reserved, and exploring that contrast can make for interesting stories.
Emotional support is also a big theme. The pregnant reader may have moments of doubt or worry, and Grillby is there to offer comfort. He might listen to the reader's concerns about becoming a parent and reassure them with his calm presence and kind words. This shows the deep emotional connection between them during this special time.