I also like the storylines where the love triangle is resolved in an unexpected way. For instance, in some fanfictions, Finn realizes that he doesn't need to choose between two characters, but instead, he forms a strong friendship with both of them. This shows a different side of love and relationships that goes beyond the traditional romantic love triangle concept.
My favorite pairing in Adventure Time Finn love triangle fanfiction is Finn with Flame Princess. Their relationship is full of passion and energy. The storylines where Finn has to prove his love to Flame Princess against all odds are really engaging. For example, when he has to face challenges in the Fire Kingdom to win her heart back after a misunderstanding.
The relationships in Adventure Time Finn love triangle fanfiction are also influenced by the other characters in the show. Jake, Finn's best friend, often provides advice and sometimes comical interference. His perspective on Finn's love life can be a guiding force or a source of confusion for Finn. Also, the Ice King's wacky antics can sometimes accidentally impact the love triangle. He might kidnap one of the characters involved, which then throws the whole relationship dynamic into chaos.
Perhaps Finn's death is an accident. He could be exploring an uncharted area of Ooo and stumble upon a dangerous trap or ancient magic that he doesn't understand. His death shocks everyone in Ooo, and his friends start to question the safety of their continued adventures. This could lead to a whole new set of adventures for his friends as they try to come to terms with his death and make Ooo a safer place in his memory.
One popular storyline could be Finn's hair having magical properties. For example, his hair might grow uncontrollably and start to have a life of its own, leading him on an adventure to find a way to control it. Another could be a story where Finn's hair is the key to unlocking a hidden realm. Writers might also explore a plot where Finn's hair changes color based on his emotions, which then affects his adventures in strange ways.
One possible storyline could be Finn exploring the world as Fionna. He might have to deal with the different social dynamics in the female - dominated version of the Adventure Time world. Maybe he'll struggle to fit in at first but then find his own place among the characters like Cake and Prince Gumball.
One interesting storyline could be Finn and the lady having a deep conversation about the nature of good and evil in the Land of Ooo. Maybe they discuss how to handle the various villains they've encountered.
One popular pairing in the love triangle could be Link, Zelda, and Malon. Link has a connection with Zelda due to their shared destiny in saving Hyrule, but Malon has her own charm and a history with Link from his time in Lon Lon Ranch. So it makes for an interesting dynamic.
One common theme is self - discovery. Finn often goes through a process of learning more about himself as he experiences love. Another theme is friendship. Since Finn has so many friends in Adventure Time, his relationships with them are often intertwined with his romantic interests.
Yes, there are quite a few. You can find some on fanfiction websites like Archive of Our Own. Just search for 'Adventure Time Finn and Marceline love' and you'll get a bunch of stories, some exploring their relationship in different ways, like how they might have fallen in love during their adventures.
A popular storyline is when Poe and Finn get separated from the main group. They have to rely solely on each other to survive and complete a mission. It shows their individual strengths and how they complement each other.
One interesting storyline could be Huntress Wizard taking Finn on a magical quest through the Land of Ooo that he's never been on before. They could encounter strange new creatures and Finn has to rely on Huntress Wizard's knowledge of magic to survive.