Another theme is the contrast between their personalities. Moxxie is more reserved and proper while Loona is brash and moody. Fanfics play with this difference, showing how they either clash because of it or find a way to complement each other. For example, in some fanfics, Moxxie's calmness helps soothe Loona's temper, and Loona's boldness encourages Moxxie to be more adventurous.
One great 'Helluva Boss Moxxie x Loona' fanfic is 'Unexpected Bonds' on FanFiction.net. It really delves into their relationship in a unique way, exploring how they interact outside of work situations and gradually develop a deeper connection.
The main characters are Striker and Moxxie. Striker might be seen as the more dominant and aggressive one. He has his own goals and ways of doing things in Hell. Moxxie, who is associated with I.M.P., has his own set of friends and a life that gets intertwined with Striker's in the fanfic, creating a lot of interesting interactions and storylines.
You can start by looking on popular fanfic websites like Archive of Our Own (AO3). It has a large collection of fanfics from various fandoms, and you're likely to find quite a few 'Moxxie x Striker' ones there.
One popular 'Moxxie x Striker' fanfic is 'The Unlikely Bond'. It delves into a scenario where they are forced to work together on a mission and gradually develop an understanding of each other.
One possible interesting plot could be Striker and Moxxie being forced to work together on a dangerous mission. They start off hating each other but gradually come to respect one another's skills as they face various challenges.
One common theme is friendship. Since they are from different 'worlds' (in the context of their original stories), a lot of fanfictions focus on how they overcome their differences to become friends.
One common plot is a human becoming friends with a member of Loona and going on adventures together. For example, they might explore a magical world that only the Loona member knows about. Another plot could be a love story where a human falls in love with a Loona member and they have to overcome differences, like the fact that one is from a different species or a famous idol while the other is an ordinary human. There are also plots where the human helps the Loona group solve a problem, like a mystery related to their music or a threat to their group.
One common theme is friendship turning into something more. For example, they start as just fans or acquaintances and then develop deeper feelings. Another theme is the exploration of the idol - fan relationship in a more personal and emotional way.
One common plot element is the meet - cute. It could be at a concert, a fan - meet, or just by chance on the street. Another is the reader helping a LOONA member through a difficult time, like dealing with the pressures of idol life.