Well, in a 'Fairly OddParents' baby fanfiction, you could have a story where the baby of one of Timmy's friends discovers Cosmo and Wanda's fairy world by accident. The baby gets lost in that world and Timmy, with the help of his fairy godparents, has to go on a quest to find the baby. Along the way, they meet all sorts of strange and wonderful fairy creatures that either help or hinder their search.
One idea could be a fanfiction where Timmy's new baby sibling gets fairy godparents too. Maybe they have really unique and wacky wishes that cause all sorts of chaos in Dimmsdale. Another idea is a story where a baby from another dimension ends up in Dimmsdale and the Fairly OddParents have to figure out how to send it back while also taking care of it.
Well, you could write a 'fairly oddparents fanfiction' where the roles are reversed. For instance, the fairies become the ones in need of help and Timmy has to use his non - magical human skills to save them. Or perhaps a story set in the future where Timmy has grown up and is now a fairy godparent himself, and he has to guide a new, young kid. You could also do a crossover with another kids' show universe, like having some characters from that universe end up in Dimmsdale and interact with the 'fairly oddparents' characters.
Another interesting concept is to write a fanfiction where a new character enters Dimmsdale. This character has a strange connection to the magic of the fairies, and it causes all sorts of chaos and new adventures for Timmy and his friends. Maybe this new character is from a parallel dimension where the rules of magic are different.
Maybe an OC who comes from a long - lost family of fairies. This OC could be on a quest to discover their family's past and their rightful place in the fairy world. They could encounter various characters from the Fairly OddParents universe along the way and have all sorts of adventures with them.
One idea could be a crossover with 'The Powerpuff Girls'. The Fairly OddParents' magic could interact with the superpowers of the Powerpuff Girls in really fun ways. For example, Timmy could wish for super strength like Buttercup, but with a magical twist. Maybe his strength would be based on how many good deeds he's done recently.
One idea could be that Jess from 'New Girl' somehow discovers she has fairy godparents like in 'Fairly OddParents'. Maybe she wishes for a perfect roommate and Timmy's fairies, Cosmo and Wanda, get sent to her by mistake. Then all kinds of wacky adventures start as they try to figure out how to get back to Timmy while also helping Jess with her life in the loft.
One interesting storyline could be Timmy Turner using his fairy godparents' wishes in creative ways to solve problems in the human and fairy world simultaneously. For example, he might wish for a device that can translate all languages so that he can communicate with fairies from different regions and help them resolve misunderstandings. Another could be a story where Vicky, his babysitter, gets a taste of her own medicine through a wish gone wrong and has to experience what it's like to be in Timmy's shoes for a day.
One idea could be a story where Timmy's new baby sibling gets fairy godparents too. Maybe they have some really unique wishes that cause all sorts of wacky adventures in Dimmsdale. Another could be a fanfiction where the baby is actually a magical being in disguise and the fairies have to protect it from evil forces.
First, know the characters well. Since it's about a baby in the 'Fairly OddParents' world, think about how the existing characters like Timmy, Cosmo, and Wanda would react to a baby. Second, come up with a unique plot. Maybe the baby has a special power or is in some kind of danger. Third, add humor. The show is known for its humor, so make the baby do cute and funny things.
The most interesting part is the clash of different power systems. Naruto has his chakra - based ninja skills and the Fairly Oddparents have their magic. When these two collide in a crossover, it creates unique and unexpected scenarios. For example, Naruto might use his shadow clone jutsu while Cosmo and Wanda use their magic to multiply the clones further. It's a wild combination.
One popular 'Fairly OddParents' fanfic could be those that explore what would happen if Timmy had different godparents with unique powers. For example, a fanfic might introduce a godparent who can control time and how that would change the dynamics of Timmy's wishes and adventures.