One idea could be creating an OC who is a new neighbor in Springfield. They could have a really unique hobby, like collecting antique typewriters. This OC could then interact with the Simpson family in various ways, like getting into a friendly competition with Homer over a barbecue recipe.
You could create an OC who is a brilliant inventor but also a bit of an eccentric. This character could move to Springfield to start a new life and end up befriending Lisa. They could work together on some environmental projects, like inventing a new type of recycling machine. Their interactions with the other characters, especially Homer who might not understand their high - tech ideas at first, could make for great fanfiction stories.
One idea could be exploring what would happen if Homer got a different job, like becoming a famous artist. It would be fun to see how his new career would change the family dynamics.
Well, a great Simpsons fanfiction concept might be centered around Mr. Burns getting amnesia and forgetting he's rich. He then starts living a normal life and has to learn about kindness and friendship from the other Springfield residents. Also, you could write a fanfic where Nelson actually has a soft side and befriends Lisa, and they have adventures together. And there could be a story where Krusty the Clown tries to retire but the town won't let him because he's such an important part of Springfield's culture.
One interesting concept could be new character backstories. For example, an OC (original character) might be a long - lost relative of the Simpsons family with a unique past that ties into Springfield's history. Another could be different takes on existing storylines. Maybe an OC changes the outcome of a well - known episode by their actions.
One idea could be a crossover with 'Futurama'. The Simpsons characters could travel to the future and interact with Fry, Bender and the rest. Maybe Homer gets a job at Planet Express and causes all kinds of chaos with his clumsiness. Another could be a crossover with 'South Park'. The two sets of very different characters would create a really comical and chaotic situation. For example, Bart could get into a prank war with Cartman.
One interesting concept could be the unique character interactions. Since it's a harem fanfiction, there might be various romantic or comical interactions between the original characters from The Simpsons and the original characters (OCs). For example, how the OCs with different personalities fit into the Simpsons' world and interact with Homer, Marge and the others.
One interesting Simpsons fanfic idea could be a story where Homer discovers a hidden talent for painting and becomes a famous artist in Springfield. Another could be about Lisa starting a new club at school that promotes environmental awareness in a really creative way. And a third idea might be a fanfic where Bart travels to the future and sees how Springfield has changed.
Another could be a fanfiction where Moe has a secret talent for art and Marge discovers it. She then encourages him to show his work in the local art exhibition, which causes a stir in the town as no one expected this side of Moe. This could explore their friendship and how they support each other in achieving new things.
One idea could be a story where Bart and Lisa team up to solve a mystery in Springfield. Maybe there's a strange occurrence at the school and they use their unique skills, Bart's street smarts and Lisa's intelligence, to figure it out.
One idea could be that Slender Man somehow gets transported into the Simpsons' world. He might start lurking around Springfield Elementary, causing the kids, including Bart and Lisa, to feel an unexplained sense of dread. Another plot could involve Homer mistaking Slender Man for a really tall, creepy new neighbor and trying to befriend him in his typical, bumbling way.
A great idea for 'the simpsons crossover fanfic' would be a crossover with 'SpongeBob SquarePants'. Imagine Homer getting a job at the Krusty Krab and causing all kinds of chaos. Bart could also become friends with SpongeBob and they get into mischief together. Additionally, a crossover with 'Scooby - Doo' would be exciting. The Simpsons could join the Mystery Inc. gang to solve a mystery in Springfield, like a haunted mansion that turns out to be a scheme by Mr. Burns to scare people away from a piece of land he wants to buy.