One idea could be a fanfic where Harry discovers a hidden room in Hogwarts that contains ancient spells and artifacts from before the school was founded. This could lead to a whole new adventure as he tries to figure out what they are for and how to use them safely. Another idea is a story where the roles are reversed, like Hermione is the one who has the lightning - shaped scar and is the main target of Voldemort, and we see how that changes the dynamic of the story. Or perhaps a fanfic that focuses on the backstories of the minor characters, like Neville's parents before they were tortured into insanity, and how their story could have influenced Neville's journey in the wizarding world.
A cool plot for a Harry Potter fanfic could be that Harry is sent back in time to the era when the four founders were building Hogwarts. He has to figure out how to get back to his own time while also trying not to disrupt the past too much. But he also gets the chance to learn magic directly from the founders, which gives him new powers and knowledge that he can use to fight Voldemort when he returns to his time. Another idea is that the magical creatures of the wizarding world rise up against the wizards because they feel mistreated. Harry has to find a way to make peace between the two sides. And then there could be a fanfic where Harry and his friends accidentally enter an alternate dimension of the wizarding world that has different rules and magical abilities.
Well, you could have a fanfic where Voldemort uses DND - style dark magic to open portals to other dimensions. The Order of the Phoenix has to quickly learn DND - style combat and magic rules to fight off the new threats that come through these portals. Harry could be sent on a special mission to find a DND - style mage who can teach them the counter - spells. Meanwhile, the Death Eaters are also trying to master this new form of magic for their own evil purposes. This would create a really exciting and unique story.
Perhaps a plot where the protagonist can choose to either side with the Ministry of Magic during a time of political unrest within the wizarding world or join a rebel group. This would involve different magical battles and moral dilemmas depending on the choice. In the 'harry potter cyoa fanfic', this could show different aspects of the wizarding society that we don't often see in the original books.
A cool plot for a Harry Potter Twilight fanfic could be a competition. The wizards from Harry Potter and the vampires and werewolves from Twilight compete in a series of challenges. These challenges could test both magic and the unique abilities of the Twilight characters. Or perhaps a love triangle between a Harry Potter character, a Twilight vampire, and a Twilight werewolf. It would be interesting to see how the different cultures and powers interact in matters of the heart.
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.
One idea could be that a dragon escapes from Gringotts and Harry has to use his skills to track it down. Maybe the dragon has a special connection to a powerful dark magic item that Voldemort was after.
One idea could be that Voldemort somehow enters the Runescape world to seek more power. Harry and his friends follow him there to stop him. They have to learn the rules of Runescape quickly to be able to fight Voldemort. Another idea is that a Runescape wizard discovers a portal to the Harry Potter world and brings some of the unique items from Runescape, like special runes, which causes a stir in the wizarding world.
A great plot for a Harry Potter academy fanfic might be a time - travel scenario. A group of students accidentally travel back in time to the founding days of Hogwarts. They have to navigate the different rules and attitudes of that era while also trying not to change history too much. Or perhaps there's a plot where a student is wrongly accused of a major crime at the academy and has to prove their innocence. They'll need to use their wits and the help of their friends to find the real culprit.
Perhaps in the fanfic, the snake is a key to unlocking an ancient magic that has been lost in the wizarding world. This could lead to a whole new adventure for Harry and his friends as they try to understand and use this magic.
One idea could be a fanfic where a character discovers a long - lost wand with a special power. For example, a wand that can open portals to different magical realms. The character then has to figure out how to use this power without getting into too much trouble with the Ministry of Magic.
One interesting plot idea could be exploring what would happen if the Sorting Hat made different decisions for the main characters. For example, if Harry was sorted into Slytherin instead of Gryffindor, his entire journey would be radically different. He might have had different friends, different enemies, and a different approach to dealing with Voldemort.