One idea could be a story where a young wizard befriends a goblin who has been wrongly accused of stealing a powerful magical artifact from Gringotts. The wizard sets out to prove the goblin's innocence.
Perhaps a fanfic where goblins start to lose their magical abilities due to a dark curse. A group of Hogwarts students, including Harry Potter, team up with the goblins to find a way to break the curse. They would have to explore the deep secrets of goblin magic and face many challenges along the way.
One interesting plot could be a goblin rebellion against the wizarding world's control over their banks. They might use their knowledge of magic and hidden tunnels to stage a takeover.
One interesting plotline could be how the characters deal with the complex nature of goblin debt. For example, Harry might find himself in a situation where he has to repay a debt to the goblins in a unique way, perhaps by using his magical skills in a task that benefits the goblin community. This could lead to a series of adventures and new relationships with goblin characters.
Well, it might be that Harry discovers a hidden goblin training ground. There, he learns unique magic skills not taught at Hogwarts. Maybe he's taught how to use ancient goblin-made weapons in combat, which gives him an edge in fighting dark wizards.
One interesting aspect in some fanfiction is the goblin society. They may have complex hierarchies and cultural traditions. There could be goblin characters who are rebels against the traditional goblin - wizard relationship, seeking more equality or even trying to take over wizarding institutions.
A really exciting plot could be that there is a prophecy that involves both Harry Potter and the goblins. The goblins have their own ancient prophecies that seem to connect with the ones about Harry. They have to work together to figure out what the prophecies mean and prevent a great disaster from befalling the wizarding world. This would involve a lot of research into old goblin and wizard lore, and they would have to travel to different magical places to find the missing pieces of the puzzle.
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.