Another interesting concept is a Kryptonian OC who is part of a secret society on Earth. They keep their identity hidden from the world, but within this society, they use their powers to maintain order and justice in a more shadowy way. They might have to deal with internal power struggles within the society as well as external threats to their secrecy.
A cool Kryptonian OC fanfiction concept could be about a Kryptonian who was exiled from Krypton for a crime they didn't commit. They land on Earth and have to prove their innocence while also dealing with their new life here. Their powers could be fading because of the different environment, and they have to find a way to regain them. Maybe they team up with some of Earth's heroes or anti - heroes to achieve this.
Maybe the OC Kryptonian has a power that is malfunctioning. They struggle to control it and it causes problems within the Justice League at first. But through the help of other members like Superman, they learn to master it. This could lead to a story of self - discovery and friendship within the team. They could face a villain who specifically targets their power, making it a race against time to get it under control.
In this fanfic, there could be a scenario where Batman is exposed to Kryptonian technology that gives him some Kryptonian - like abilities temporarily. A Kryptonian comes to Earth to study this anomaly. They start off as adversaries but as they learn more about each other, they find that they can work together to protect Earth from a greater threat that only their combined skills can defeat.
One idea could be that Naruto is somehow given Kryptonian powers. He might start using his newfound super strength and flight in his battles in the ninja world. For example, he could use his super speed to outmaneuver opponents more easily during a fight with Akatsuki members.
Well, a plot could be that the reborn character discovers a hidden power within Kryptonian abilities that no one else knew about. This could put them in a position where they are both feared and revered. Also, they could form an unlikely alliance with a group of Kryptonians who were considered outcasts. Together, they try to bring about a new era on Krypton. Another interesting plot would be the character being sent on a mission to a different planet. Since they are reborn as a Kryptonian, they have unique skills for this mission and face various challenges during it.
An interesting MCU OC fanfic idea could be an OC who is a journalist. They are always on the hunt for the next big story about the superheroes. This could lead them into all sorts of dangerous situations as they try to get exclusive interviews or expose secrets. Another could be an OC who is a mutant in the MCU (even though mutants are not as prominent yet). This OC would have to deal with being different and feared, while also trying to use their powers for good. And a third idea is an OC who is a reformed villain. They were once on the wrong side but now want to make amends and help the heroes in their fight.
A Sonic OC fanfic could center around an OC who is a healer. In a world full of battles against Dr. Eggman, this OC would use their healing powers to patch up Sonic and the gang after tough fights. They could also have a backstory about how they learned their healing abilities, maybe from an ancient and forgotten tribe in the Sonic world. This would add depth to the character and the fanfic as a whole.
You could write an OC fanfic where the OC is a female assassin. She has a rivalry with Agent 47 at first, thinking he is taking all the good contracts. But as the story progresses, they end up having to team up to take down a powerful criminal organization that is targeting assassins. Her special skill could be hacking into high - security systems to gain access to targets.
A Hiccup OC fanfic could also explore what would happen if Hiccup's OC was from a different tribe. They could have different traditions and skills, and the story could focus on how Hiccup and his friends learn from this new character. For example, the OC could teach them a unique way of dragon training that they've never seen before.
You could have an OC who is a shy artist fairy. In the fanfic, Tinkerbell discovers the OC's amazing talent for painting the most beautiful landscapes of Neverland. They then team up to create a huge mural in Pixie Hollow that showcases all the different areas of their magical world. The OC might start off really timid but gain confidence with Tinkerbell's encouragement.