Peppermint Butler could be an interesting character to pair with the Ice Princess. His mysterious and somewhat dark nature could add an element of intrigue to the story. Maybe he has a task for the Ice Princess that she initially refuses but then gets drawn into. Lady Rainicorn would also be a good choice. Since she can't talk in a language that the Ice Princess can understand easily, it could lead to some comical misunderstandings at first, but then they could develop a unique bond. And Lemongrab, his strange and often unpredictable behavior could create a really unique dynamic when paired with the Ice Princess.
Finn and Jake are great choices. Finn's heroic nature and Jake's laid - back but powerful abilities can create interesting interactions with the Ice Princess. Another good one is Marceline. Her vampire nature and the Ice Princess' ice powers could lead to some cool battles or alliances. Princess Bubblegum could also be a good pairing as they are both princesses, and their different personalities, PB's scientific mind and the Ice Princess' more emotional nature, could make for a great story.
The Lumpy Space Princess could also be paired with the Ice King. Her sassy attitude could contrast with the Ice King's craziness. In a fanfiction, they could end up on an adventure together where the Lumpy Space Princess tries to 'fix' the Ice King or just uses him for her own gain in a really comical way.
Finn would be a great character to pair with the Lich. Finn is the hero, so the contrast between his good - natured self and the Lich's evil would create a lot of interesting story possibilities. They could have some epic battles or, as I mentioned before, an unexpected alliance.
Riley would be a great character to pair with the ice princess. Riley is known for her open - mindedness and eagerness to learn. She would be curious about the ice princess's powers and world, and they could have a lot of adventures together, like exploring the city in winter and the ice princess using her powers to create beautiful ice sculptures.
In Adventure Time fanfiction, the Ice Princess could find allies in many characters. Lady Rainicorn could be one. Her flying abilities and combat skills could be very useful for the Ice Princess. BMO could also be an unexpected ally. BMO might have some knowledge or technology that could assist the Ice Princess in her adventure. Additionally, Flame Princess could be an ally under certain circumstances. If there is a threat that endangers both the Ice Kingdom and the Fire Kingdom, they could put aside their differences and work together.
Naruto and Finn are often paired. They are both the main protagonists in their respective shows and have a lot of similarities. They are brave, determined, and always looking for adventure. Their combined energy would make for an exciting story.
The Ice King can also be a part of adventure time bandit princess fanfiction. He might try to capture the Bandit Princess for his own strange reasons, like wanting her to be his ice princess. His bumbling nature and ice powers create comical and challenging situations in the story.
The Ice Princess stood in her glacial domain, her icy hair flowing like a frozen waterfall. She was lonely, as always. One day, Finn and Jake came by on an adventure. They were initially cautious, but Finn's kind heart reached out to her. Jake, with his goofy charm, made her laugh for the first time in ages. They decided to have a snowball fight, and the Ice Princess found herself truly enjoying the company. This simple encounter changed her view of the outside world.
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.
I'm not sure who the 'best' is exactly, but there are many talented writers out there. Some popular ones might be those who have been writing in the Adventure Time fanfiction community for a long time and have a large following. They usually have a good understanding of the characters of Finn and the Fire Princess and can create engaging stories.
Obviously, Finn and the Jungle Princess are the main characters. Finn, a brave and adventurous boy, and the Jungle Princess, who has her own set of skills and knowledge about the jungle environment.