A common theme could be friendship. Mayor X and Isabelle might be shown having adventures together in their town or helping each other out with various tasks.
Another theme could be leadership. Since one is a mayor, the fanfiction might explore how Mayor X leads the town with Isabelle's assistance. It could show how they work together to make the town a better place, like organizing events or dealing with difficult villagers. Also, there could be themes of discovery. Maybe they discover a new part of the town or a new aspect of the game's world together, which makes for an interesting story arc.
One common theme is friendship development. Since Isabelle is often the assistant to the Mayor, fanfics usually explore how their relationship changes from a strictly professional one to a deeper friendship or something more. Another theme is problem - solving. They might work together to solve issues in the village like dealing with a cranky villager or a natural disaster in the game world.
I'm not sure which specific 'Mayor X Isabelle' fanfiction is available. You could try searching on fanfiction websites like Archive of Our Own or FanFiction.net. They usually have a wide variety of fan - created stories.
One plot idea could be that Isabelle and the Mayor have to work together to save the town from a natural disaster. They face many challenges during the process and in the end, their bond grows stronger. Another could be a story where Isabelle discovers a long - lost secret about the Mayor's family and they embark on a journey to uncover the truth. Maybe there could also be a plot where they get into an argument over a new town policy, but then realize they need to find a middle ground for the good of the town.
Some popular themes could be friendship exploration. Since Isabelle is often seen as a helpful character and the mayor has a leadership role, their interactions in fanfics might focus on building a unique friendship. Another theme could be problem - solving in the town. They might team up to deal with various issues like a shortage of resources or a local event that has gone awry.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). There are often a lot of different fanfictions for various fandoms there. Another place could be FanFiction.net. Just search for 'Isabelle x Mayor' and you might find some interesting reads. You can also check out Tumblr. Sometimes fans post their fanfiction there or link to other places where it can be found.
Romance is also quite prevalent. Writers might explore the relationship between Isabelle and the wolf, how they fall in love, overcome differences, and build a relationship. There could be cute moments of flirting and getting to know each other.
A common theme is leadership. Fanfictions often explore how Mayor Bubba leads the town, makes decisions, and deals with political opposition.
I'm not sure of the exact name, but there's a fanfic where Isabelle helps the Mayor organize a big festival in the village. It shows how well they work together and how their friendship might be evolving into something more. It has detailed descriptions of the preparations for the festival, from decorating the town square to inviting all the villagers. The way Isabelle and the Mayor interact during this process is really charming, and it gives a great insight into their characters in a different scenario than the normal gameplay.
A theme of redemption can also be present. If one of the characters has made mistakes in the past, the kiss from Isabelle or Hugo can be a sign of forgiveness and a new start. It can be a very emotional moment that ties into a larger story arc of the character growing and changing for the better.
A common trope is the 'enemies to lovers' or at least 'rivals to lovers'. Since they have different personalities and ways of doing things in the Shadowhunter world, it can be interesting to see how they overcome their differences. Another is the 'hurt/comfort' trope, where one of them gets injured or is in a difficult situation and the other provides support and care.