There are many possibilities. You could write a story about Moonjumper's adventures in a new world or a tale of his friendship with other characters.
Moonjumper fanfic could explore a romance angle for him or take place in an alternate universe where the rules are completely different. Maybe he has to save the entire time-space continuum!
One common theme is mystery. Moonjumper is a rather mysterious character, so many fanfics explore his secrets. Another is adventure, as it ties in with the overall adventurous nature of 'A Hat in Time'. For example, fanfics may have Moonjumper going on quests to different parts of the game world.
Sure. One great 'A Hat in Time Moonjumper Fanfic' is 'Moonjumper's Adventure'. It delves deep into Moonjumper's backstory and his relationship with the other characters in the game world. Another interesting one could be 'Moonjumper and the Time Rifts', which creates an exciting plot around Moonjumper's attempts to fix the time rifts. There's also 'The Secret of Moonjumper', which reveals some hidden secrets about this mysterious character.
Well, maybe a romance fanfic where the characters encounter each other among the blue flowers under the moonlight with the nighthowlers adding an element of danger or mystery. Or it could be a science fiction story involving some kind of experiments with the blue flowers and the nighthowlers being part of a strange conspiracy.
Well, one idea could be a fanfic that explores the backstories of the main characters in Don Regular Show and how it shaped their present. Another could be a crossover fanfic where they interact with characters from another popular show.
Maybe a fanfic exploring the characters' lives after the ending of the movie. It could focus on how they cope with the ongoing challenges and build a new normal.
You could write a fanfic exploring Bryce's backstory and what led him to his actions in the show.
Well, one could create a new story plot after being based on a fanfic. For example, you might develop a new adventure for the characters in the fanfic. You could also create new character relationships. Maybe in the original fanfic two characters were just friends, but after basing on it, you make them into rivals or lovers.
It could be a humorous adventure story where Master and Ten team up to solve a mystery involving lemon-related oddities in the Doctor Who universe.
You could come up with a story where they team up to face a powerful and ancient evil that threatens the entire universe.
It could be a romantic story where two people meet and fall in love in a flower garden.