An OC with the ability to turn invisible could be another great addition. On a trip to a museum, the OC accidentally activates their invisibility while exploring a restricted area. The rest of the class has to use their knowledge of science to find and bring back the OC, all while learning about the exhibits in the museum.
One idea could be an OC who has a special power related to time. They could accidentally send the Magic School Bus to different eras in history, creating all sorts of chaos and educational adventures. For example, they might end up in the Ice Age and have to figure out how to survive and learn about the animals and climate of that time.
One idea could be a crossover with 'Harry Potter'. The Magic School Bus could take the students to Hogwarts. They could learn about magic from the Hogwarts professors and compare it with their own scientific knowledge. Maybe they'd help Hermione solve a complex potion problem using scientific methods.
One idea could be an OC who has a unique magic ability that is not recognized by the traditional magic system in the school. For example, the ability to manipulate time in a very limited and personal way, like being able to re - live a few seconds to correct a mistake in a spellcasting. This would lead to conflicts as the school authorities try to figure out if it's a new form of magic or something dangerous.
There's often an OC named Lily who is a brilliant inventor. She always comes up with cool gadgets that help the Magic School Bus on its adventures. For instance, she might create a device that can analyze the chemical composition of a strange substance they encounter during a trip to an alien planet in the fanfiction.
A possible plot is that the OC is a misfit who doesn't fit into the typical categories in the High School DxD world. They might be a human with no obvious supernatural powers at first, but through their wits and determination, they manage to form alliances with different factions. They could use their knowledge of human technology and psychology to gain an edge, and along the way, they develop a unique power or ability that no one expected.
One idea could be an OC who is a new transfer student at the high school in the Bleach universe. They have a hidden power that starts to surface when they encounter Hollows on school grounds. Another could be an OC who forms an unlikely friendship with a Soul Reaper in disguise at the high school and together they face off against a powerful Menos Grande that has targeted the school.
A possible plot in High School DxD Torture Magic Fanfiction is that there is a magical artifact that is powered by torture magic. Different factions in the High School DxD world are vying for this artifact. The story could follow the main characters as they try to either obtain the artifact for good reasons or prevent it from falling into the wrong hands. Along the way, they face many challenges related to the torture magic associated with the artifact, like having to resist its corrupting influence.
One idea could be an OC with the power to control water in unique ways, like creating ice sculptures that can come to life. Another could be an OC who has the magic to communicate with mythical animals and use them as allies. Maybe an OC with magic that allows them to manipulate time on a small scale, like freezing time for a few seconds during a battle.
One idea could be an OC who is a gamer in the High School DxD world and uses their gaming knowledge to strategize in battles. For example, they might use their understanding of RPG leveling systems to level up their own powers faster than others.
Perhaps the OC is a transfer student from a different village. Gaara is intrigued by her different ways and culture. They start to study together about each other's backgrounds. As they do this, they fall in love. The high school setting could add elements like jealous classmates or strict teachers that try to keep them apart, but they overcome these obstacles.
Well, an OC who is a talented artist but is too shy to show their work could be a great plot. The ponies in Ponyville discover the OC's talent and encourage them to share it. Or an OC with a time - traveling ability. They accidentally mess up the timeline in Equestria and have to work with Twilight and her friends to fix it.