One idea could be a crossover where characters from the Originals visit Hogwarts. They could interact with the students and teachers, and perhaps there could be a magical mystery that they all have to solve together. For example, a dark magic spell that is affecting both the wizarding world and the vampire/werewolf world in the Originals.
A plot could involve a time - travel scenario where a character from the Originals goes back in time to the era of the founders of Hogwarts. They might accidentally change something in the past that has a huge impact on both worlds in the present. This would lead to a series of adventures where characters from both universes have to work together to set things right.
Maybe a fanfic where a character from the Harry Potter universe, like Hermione, discovers a hidden connection to the Originals' world. She could use her intelligence to figure out how the different magical systems work in both worlds and try to bring peace between warring factions in the Originals' realm while also dealing with threats in her own world.
One interesting plot idea could be a crossover where characters from 'Harry Potter' and 'The Originals' have to team up to fight a common dark magic threat. For example, Harry Potter and Klaus Mikaelson might initially be at odds due to their different views on magic use and power, but they realize they need each other's skills to defeat a powerful ancient evil that is threatening both the wizarding world and the vampire - werewolf - witch community in 'The Originals'.
Well, a great fanfiction idea within 'Harry Potter the originals fanfiction' is to focus on the relationships between different generations. Maybe how the founders' relationships with their students influenced the future of Hogwarts. Also, imagining new magical creatures that could exist in the wizarding world and how they interact with the known characters. This would add more mystery and excitement to the existing world of Harry Potter.
One idea could be to cross the characters with another popular supernatural show's characters. For example, bringing in some characters from 'Buffy the Vampire Slayer' and seeing how they interact with the originals. Maybe Buffy could team up with Klaus to fight a new, powerful enemy that threatens both their worlds.
In some fanfics, a plot twist could be that a character from The Originals turns out to be related to a major Harry Potter character. For example, it might be revealed that a vampire has a long - lost wizard relative in the Potterverse. It completely changes the dynamics of how the two worlds interact.
One idea could be Harry Potter arriving in Skyrim and using his magic to combat the dragons. Maybe he teams up with the local mages and they learn from each other's magical techniques.
One idea could be exploring what would happen if a new, mysterious student joined Hogwarts during the Triwizard Tournament. This student could have a hidden agenda related to the Dark Arts and start influencing the events of the tournament in unexpected ways.
One interesting plot idea could be Harry's return to Hogwarts as a teacher. He could pass on his unique experiences and knowledge to the new generation of students.
One idea could be a dragon that forms a bond with Harry and helps him in his battles against Voldemort. Maybe the dragon has some special powers that are crucial for Harry to win.
One idea could be Harry and his friends exploring new magical realms that were previously unknown. Maybe they discover a hidden school of magic that has a different approach to teaching spells.
Another plot could focus on the lives of the secondary characters from the original series. For example, Neville could be the head of Herbology at Hogwarts and discovers a new, dangerous plant that has some sort of connection to an ancient magic. The 'carry on fanfic' could then be about how he and his students deal with it, with some cameos from the main characters.