A great plot might involve a dragon that was once an experiment by Voldemort. Harry befriends this dragon which has some unique powers due to Voldemort's dark magic. The dragon could have the ability to sense dark wizards and their plans. Harry uses this to his advantage to stop various plots against the wizarding world. Also, the dragon and Harry could go on a journey to find a way to reverse the dark magic effects on the dragon.
One plot idea could be that Harry discovers a baby dragon in the Forbidden Forest. He decides to hide and protect it from the Ministry, which would want to destroy it. As the dragon grows, it helps Harry in his battles against the Dark Arts, using its powerful fire-breathing ability to fend off Death Eaters. Another could be that the dragon is a shape - shifter and can turn into a human form, becoming Harry's closest confidant at Hogwarts, sharing secrets and helping him solve mysteries.
One plot idea could be that Harry's sister is secretly a powerful witch with unique abilities. For example, she might have the power to communicate with magical creatures in a way no one else can. This could lead to her getting involved in a plot to save a rare and endangered magical creature that is being hunted by dark wizards. Another idea is that she discovers a hidden prophecy related to her and Harry that changes the course of their fight against Voldemort. She could be the key to a new spell or magic that can defeat Voldemort once and for all.
One plot idea could be that the nanomachines are secretly placed in Hogwarts by a dark wizard. They start to manipulate the magic in the school, causing strange things to happen like spells going haywire. Harry, with the help of his friends, has to figure out how to stop the nanomachines before they destroy the balance of magic at Hogwarts.
She could inherit some of the traits from Harry's past enemies in a strange way. Maybe she has a bit of Voldemort'sParseltongue ability which scares her at first. But then she learns to use it to her advantage, like being able to enter hidden areas where only Parseltongue speakers can go. This could lead to her finding lost magical artifacts that have been hidden away for centuries. Also, her relationships with her classmates could be complex. Some might be jealous of her, while others might try to use her for her father's fame.
Well, perhaps his husband is a powerful auror as well. They team up to fight against a new dark force that is emerging in the wizarding world. Their relationship adds an extra layer of depth to their fight as they not only have to protect the world but also their relationship. They might face challenges from traditional wizarding families who are not accepting of their relationship at first.
Perhaps Harry's different father could be a Muggle - born wizard who was experimented on by dark wizards. This would give Harry a connection to a darker side of magic that he has to come to terms with. He might have inherited some unique powers or curses from his father. Or his father could be a wizard who was in hiding from Voldemort for reasons other than what we know in the original story. This could change the dynamic of the prophecy and Harry's role in the fight against Voldemort.
One plot idea could be that the lost sister was separated from Harry during the attack on their parents. She could be raised in a different magical family, and when she discovers her true identity, she has to navigate between her new family and her connection to Harry. Another could be that she was hidden away by Dumbledore for her own protection and has unique magical abilities that Voldemort wants to use. When she enters the wizarding world, she becomes a target but also a powerful ally to Harry.
One plot idea could be Harry discovering a new, ancient magic that gives him an extreme boost in power. He could use this power to reform the wizarding world's laws for the better. Another could be that Harry has a power transfer from an old, powerful wizard and has to learn to control it while facing new dark threats. Maybe he uses his newfound power to create a school for underprivileged young wizards and witches.
Another plot could be that the dragon egg is actually a trap set by the Death Eaters. They want Harry to take the egg so that they can track him. However, Harry figures out their plan and instead uses the dragon egg to his advantage. He uses it to mislead the Death Eaters and at the same time, he discovers a way to turn the dragon into an ally.
A great plot could be that the goblin is a time - traveler. It has come from a future where Voldemort has won and is trying to change the past. The goblin teams up with Harry, using its unique goblin magic and knowledge of the future to give Harry an edge in the fight against the dark forces. They might have to travel to different magical locations and enlist the help of other magical creatures.
One possible scenario in such a fanfic could be that Harry discovers a dragon egg during one of his adventures outside Hogwarts. He secretly takes care of it, using his knowledge of magic to keep it warm and protected. As the dragon hatches, it forms an immediate bond with Harry, recognizing him as its caregiver. This dragon could then help Harry in his battles against dark forces, providing an extra element of power and surprise.