One great Finn x Marceline fanfic is 'Adventure in the Night'. It beautifully explores their relationship in a post - apocalyptic setting. The author does an amazing job of portraying Finn's growth and how he and Marceline interact in this new world.
I really like 'Finn and Marceline's Unlikely Alliance'. It shows a unique take on their relationship where they start off as reluctant partners but end up having a strong bond. There's also 'Marceline's Song for Finn' which is a more emotional fanfiction that focuses on Marceline's feelings towards Finn through her music.
I really like 'Finn and Marceline's Night Out'. In this fanfic, they have a sort of double - date situation with Jake and Lady Rainicorn which leads to some really funny and heartwarming moments. It shows a different side of their relationship in a more comical setting.
You can start by looking on Archive of Our Own (AO3). It has a large collection of fanfics, and you can easily search for Finn x Marceline ones. Just use the search bar and type in the relevant tags.
You can find 'Marceline x Finn fanfiction' on websites like Archive of Our Own (AO3). It has a large collection of fanfictions from various fandoms, including Adventure Time. Another good place is FanFiction.net, which has been around for a long time and has a decent amount of Adventure Time fanfictions.
Some Tumblr blogs are also dedicated to sharing and discussing Finn x Marceline fanfiction. You can search for relevant tags on Tumblr, like '#FinnxMarceline fanfic' and you might find some great recommendations or even some exclusive fan - made stories.
In one fanfiction, Finn and Marceline start off as friends who slowly realize their feelings are deeper. Finn, always the brave adventurer, begins to notice how much he misses Marceline when she's not around. Marceline, for her part, sees Finn's kindness and courage in a new light. One day, during a dangerous adventure where they protect the Candy Kingdom together, they share a moment of closeness that makes their relationship shift towards love.
In fanfiction, their relationship could be developed by having them team up for a noble cause, like saving the Candy Kingdom from a new threat. During this mission, they face challenges that require trust and cooperation. Finn might learn to be more patient with Marceline's mood swings, and Marceline could come to appreciate Finn's unwavering optimism. Also, they could have a friendly competition that turns into a deeper understanding of each other's strengths and weaknesses.
A Marceline and Finn kiss in fanfiction can be really interesting. It might show a different side of their relationship. Maybe in the fanfic, it's a moment of realization for both of them, a deeper connection that goes beyond their usual adventures. It could also be a turning point in the story, leading to new plot developments like them facing challenges together as a couple or dealing with how their friends react to this new relationship.
Adventure is a major theme too. Since they are in the world of Adventure Time, they go on quests and have escapades. This theme allows for a lot of action and exploration in the fanfics. And there's also the theme of trust. As their relationship develops, they learn to trust each other more and more, which is a key part of their story.