One popular plotline is the Ice Queen's journey to find true friendship. In many fanfictions, she starts off as a lonely and misunderstood character. Another plotline could be her attempts to gain more power in the Land of Ooo, which often leads to conflicts with other characters like Finn and Jake. Some fanfictions also explore her past and how she became the Ice Queen in the first place.
Well, a common plotline is the Ice Queen falling in love. This might seem out of character at first, but in fanfiction, it can be really interesting. She could fall for a new character or even have a strange relationship with someone like Marceline. Also, there are plotlines where she has to team up with her enemies to fight a greater threat to the Land of Ooo. This shows her more complex side and how she can put aside her differences for the greater good.
Some fanfictions focus on the Ice Queen's redemption. Maybe she realizes that her actions have been causing harm to the Land of Ooo and its inhabitants. So, she tries to make amends. This could involve helping the Candy Kingdom rebuild after she has attacked it or trying to be nicer to Finn and Jake. There are also plotlines where she discovers a new magical ability and has to learn how to control it, which causes all sorts of adventures and mishaps.
Power and its consequences is also a frequent theme. The Ice Queen has powerful ice - based abilities. Fanfictions might delve into how she uses or misuses her powers, and how it affects her relationships with others in the Land of Ooo. Some fanfictions also focus on her backstory, trying to explain how she became the way she is, which could involve themes of loneliness and isolation as she is a rather solitary character in the show.
One interesting 'Adventure Time Ice Queen' fanfic could be about her backstory before she became the Ice Queen. It might explore how she got her powers and what led her to be so cold - hearted.
Marceline is a very common side character in Ice Queen Adventure Time fanfiction. Their personalities are so different that it creates interesting interactions. Another common one is Princess Bubblegum. Since the Ice Queen often has conflicts with the Candy Kingdom, Princess Bubblegum is bound to be involved. Also, Peppermint Butler sometimes shows up as he is often associated with Princess Bubblegum's court and can add an element of mystery to the story.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of Adventure Time fanfictions, including those about the Ice Queen. Just search for 'Adventure Time Ice Queen' in the search bar, and you'll get a list of relevant stories.
A great plotline could involve Jake as a female and her unique take on being Finn's best friend. She could bring a different kind of energy to their adventures, like being more nurturing while still having that tough side when they face villains.
One interesting Ice Finn fanfiction could be about his adventures in a frozen realm that wasn't shown in the original series. Maybe he discovers a new type of ice creature and has to form an alliance with it to save the day.
One interesting fanfiction could be about the Ice King's past before he became the way he is. Maybe it explores his life as Simon and how he gradually lost his sanity while being affected by the crown.
Archive of Our Own (AO3) is also a great place to find 'Adventure Time Ice Queen' fanfics. The tagging system there is very useful. You can search for tags like 'Ice Queen', 'Adventure Time', and also filter by things like rating, word count, and genre to find the perfect fanfic for you.
Perhaps a plotline where the returning humans bring new technologies or ideas that either clash or blend well with the existing magic in Ooo. They could introduce things like new forms of communication or transportation that change the dynamics of different kingdoms. Maybe they start trading their technology for magic items, creating new economic and social relationships.
One possible plotline could be Marceline dealing with the challenges of pregnancy while still having to face the usual threats in the Land of Ooo. Maybe she has to rely on her friends like Finn and Jake more than ever for protection. Another could be exploring the relationship between her and the father of the baby, whoever that might be in the fanfiction, and how they navigate this new chapter in their lives.