You could also write a fanfiction about the 'little king' traveling to different realms. He might encounter unique cultures, strange creatures, and have to adapt to new magic systems, which would make for an exciting adventure.
One idea could be exploring the backstories of minor characters in more depth. For example, you could write about the early life of a demigod who was only briefly mentioned in the original series. Another idea is to create alternate endings to the main story arcs, like what if the heroes had made different choices during a crucial battle? You could also focus on the relationships between the characters in a different light, perhaps showing a friendship that was hinted at but not fully developed.
A fanfiction could also focus on the backstories of the less - explored characters in Dragon Ball Heroes. For instance, you could write about the origin of a particular alien race that is only briefly mentioned in the game. Explore their culture, their reasons for getting involved in the battles, and how they interact with the main characters. This would add more depth to the overall Dragon Ball Heroes universe.
A crossover with a superhero universe, say the Marvel Universe. Travis Touchdown from No More Heroes could find himself in New York City and get involved with the Avengers. Maybe he initially misunderstands their motives and gets into a fight with them, but then realizes they're on the same side against a greater threat.
A fanfiction could focus on how the ponies form an unlikely alliance with some of the Storm King's minions. They realize that they also don't like the Storm King's tyrannical ways and decide to work together to overthrow him. This would involve a lot of character development for both the ponies and the minions.
A wise old wizard could be a great side character. He could act as a mentor to the little king, guiding him in his use of magic and in making difficult decisions.
Well, you could write a fanfiction where the King of Fighters characters have to team up to fight against an otherworldly threat that is not related to their usual rivalries. This would bring out different sides of the characters as they have to cooperate in a new way. Or perhaps a story about a young fan who somehow gets transported into the King of Fighters world and has to learn to fight to survive. Also, a story about the origin of one of the most mysterious moves in the game, told from the perspective of the character who created it.
A fanfiction could also be about the hyenas getting a second chance. Maybe they find a new place to live and try to form a more positive community, with some help from the lions.
A great idea for a King the Land fanfiction is to put the characters in a completely different setting, like a tropical island. They could be there for a business retreat or just a vacation. This new environment would bring out different sides of the characters. For instance, the normally strict and professional characters might let loose a bit more. Another concept could be to write a fanfiction where one of the characters has a special power or ability that they have to keep hidden from the others at first. As the story progresses, they gradually reveal it and it changes the dynamics of their relationships. And you could also do a fanfiction where there is a competition among the hotel staff for a promotion, and the main characters get caught up in the middle of it, with their relationships being tested.
One idea could be exploring the backstories of minor characters. For example, the spirits that the shamans call upon might have their own complex histories and relationships that could add depth to the Shaman King universe.
One idea could be exploring an alternate universe where Naruto's parents didn't die. This would change his whole upbringing and how he views the world. He might not be as driven to become Hokage in the same way, and his relationships with characters like Iruka and Sasuke could be very different.