Another interesting concept is an OC who is a villain at first but later becomes an ally. Maybe they were brainwashed by the real villains. Their journey from the dark side to the good side can be full of drama, self - discovery, and interesting interactions with the Sailor Guardians.
A great concept for a Sailor Moon OC fanfic is an OC that has a special connection to the moon but not in the same way as Sailor Moon. This OC could have been created by an ancient civilization on the moon to be a protector. She might have different abilities like being able to control lunar phases for various effects, such as using a new moon to create a shield or a full moon to enhance her strength. Or an OC who is an artist, and she uses her art to fight the evil. Every time she draws something, it comes to life to battle the bad guys.
One idea could be that the OC is a new senshi from a far - off planet who arrives on Earth just as a new threat emerges. The Sailor Scouts are initially suspicious but soon realize they need all the help they can get.
One interesting plot idea could be a time - travel scenario where Sailor Moon goes back in time to prevent a major event that led to the rise of a powerful enemy. Another could be a crossover with another popular anime, like having Sailor Moon meet Naruto and they team up to fight a new threat.
One idea could be a crossover where the characters from Fairy Tail and Sailor Moon team up to fight a common enemy. For example, the powerful mages of Fairy Tail and the Sailor Guardians could combine their unique powers to defeat a dark force that threatens both their worlds. Another idea might be a story where a character from Fairy Tail somehow ends up in the Sailor Moon universe and has to adapt to the new rules and powers there. Or perhaps a fanfiction where the magic in Fairy Tail has an unexpected effect on the Sailor Moon characters, like changing their powers in strange and interesting ways.
One interesting idea could be a unique setting for the kiss, like on a magical moonlit balcony in the Crystal Tokyo. Another might be the emotions involved, perhaps a forbidden love between a Sailor Scout and an unexpected character, which adds a lot of drama to the fanfiction.
Well, in Sailor Moon dark fanfiction, a cool plot could be the Sailor Guardians facing an enemy that can manipulate their worst fears. This would make them question their own abilities and loyalties. Also, a story where the power source of the Sailor Guardians is somehow tainted, turning their powers dark and making them struggle to control it. Or perhaps a plot where a new dark Sailor Guardian emerges, with powers equal to or greater than Sailor Moon's, causing chaos in the magical world.
One idea could be a crossover with the Harry Potter universe. Sailor Moon and her friends could attend Hogwarts and have to deal with both magical threats from the wizarding world and the dark forces they usually face. For example, they might help the students at Hogwarts fight off a new kind of dark magic that has similarities to the dark energy they combat in their own world.
One idea could be that the Sailor Scouts somehow end up in the SVTFOE universe. They could team up with Star and Marco to fight a common enemy. Maybe an evil force that combines the darkness from both universes.
One idea could be that the characters from RWBY end up in the Sailor Moon universe and have to learn the ways of the Sailor Scouts. For example, Ruby could be intrigued by Sailor Moon's transformation and try to adapt her Crescent Rose to work in that magical world.
An interesting plot could be that Goku and Sailor Moon meet during a multiverse tournament where representatives from different anime universes are competing. They initially don't get along because of their different fighting styles and beliefs, but as the tournament progresses, they realize they can learn from each other. Together, they face off against a cheating opponent who is using unfair tactics to win. Through their combined efforts, they not only defeat the opponent but also learn to respect each other's worlds and ways of fighting.