One great theme is their friendship adventures. Stories that focus on their new quests and how they support each other through different challenges are always interesting. Another theme could be how they grow together as characters over time.
Well, Tumblr is also a great place to search for Finn x Jake fanfic. There are many fanfic writers who post their works there, and you can also find fan communities that might recommend some great pieces. Just use the search function and type in 'Finn x Jake fanfic' and you'll likely get some interesting results.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of various fanfictions, including Finn x Jake ones. Just search for 'Finn x Jake lemon' in the search bar and you'll likely find some relevant stories.
One popular story could be 'The Adventure Beyond the Lemon Grove'. It's about Finn and Jake stumbling upon a magical lemon grove where they have to solve various puzzles. Another might be 'Lemonade with Finn and Jake' which focuses on a day in their life where they make lemonade and have heart - to - heart conversations. There's also 'Finn, Jake and the Lemon - Colored Mystery' which is a mystery - solving adventure involving a lemon - colored object.
One interesting fanfiction could be about Finn and Jake going on a new, never - before - seen adventure in a strange magical land. Maybe they encounter a new type of magical creature that challenges their friendship and they have to work together to overcome it.
You can start by checking out popular fanfiction websites like Archive of Our Own. Just type in 'Adventure Time Finn x Jake' in the search bar and you'll get a list of relevant stories. Look for ones with high ratings and a lot of positive reviews.
One interesting Finn and Jake fanfiction could be about their adventures in a new, uncharted land within the Land of Ooo. Maybe they discover a tribe of magical creatures that they have to befriend to get a special item for Princess Bubblegum.
Adventure is a very common theme. Finn and Jake are known for their adventures in the original show, and fan fictions often continue this trend, sending them on new quests.
Finn might initially go into denial. He could keep expecting Jake to just pop back up like he always does. Then he'd probably get angry, at himself or at whatever caused Jake's death. Eventually, he'd start to accept it and try to honor Jake's memory by being a better hero.
In this fanfiction scenario, Finn and Jake as vampires might have enhanced physical abilities. Finn could be even more skilled in combat with his vampire speed and strength. Jake, with his shape - shifting ability combined with vampiric powers, could turn into some really unique and powerful forms. They might also have to deal with the typical vampire problems like avoiding sunlight and craving blood, which could lead to some interesting moral dilemmas as they try to stay true to their heroic selves.