Well, perhaps in the fanfiction, Harry's dragon form is initially out of control. He has to learn how to master it with the help of his friends, like Hermione researching ancient spells to help him gain control. Or maybe there's a prophecy related to his dragon - turning ability that makes him a target for both good and bad wizards. The story could also focus on how Harry uses his dragon form to participate in a magical tournament that usually doesn't allow such unique abilities.
One idea could be that as Harry turns into a girl, he has to navigate the different social dynamics in Hogwarts. For example, he might be treated differently by his male friends like Ron and Hermione. Maybe Ron is initially awkward around 'her' but then realizes that it's still Harry inside. Hermione could be more empathetic and help Harry adjust to the physical and social changes.
Here's a plot. Harry turns into a dragon in the Forbidden Forest. At first, he's scared and confused. But then he realizes he can fly and explore parts of the forest that are unreachable as a human. He discovers a hidden magical artifact while in his dragon form. However, the Ministry of Magic hears about his transformation and wants to capture him, thinking he's a dangerous uncontrolled magical being. So, Harry has to evade capture while also trying to figure out how to turn back to his human form and clear his name.
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.
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 interesting plot idea could be that the White Dragon Emperor somehow ends up in the Harry Potter universe. Maybe he's sent there as part of a magical experiment gone wrong. He could then use his unique powers to help Harry and his friends in their fight against Voldemort. For example, his dragon powers could be useful in battles against Death Eaters, providing an extra boost of strength and firepower.
In some fanfiction, the wand with the dragon fang could be a key to an ancient wizarding treasure. But it's protected by powerful spells. The wizard has to figure out how to unlock the wand's full potential in order to access the treasure and along the way, he meets many challenges and makes new allies.
Well, a really interesting plot could be that Harry Potter is actually a descendant of an ancient line of Holy Dragon Slayers. He uncovers this secret when he starts having strange dreams about fighting dragons. As he delves deeper into this mystery, he finds out that there is a prophecy that only he can slay a certain holy dragon that is about to awaken and cause chaos in the wizarding world. Along the way, he has to learn new spells and combat techniques specifically designed for dragon slaying. He might also face opposition from some in the wizarding community who think that slaying a holy dragon is a sacrilege.
One idea could be that as a dragon, Harry uses his new form to protect Hogwarts in a way he couldn't as a human. He could fly around the castle, breathing fire at any dark forces approaching. Another could be that his dragon form has unique magical abilities that are connected to his status as 'God Harry Potter', like being able to see into the future to prevent disasters.
One plot idea could be that the fem dragon is a guardian of an ancient wizarding artifact. Harry discovers this and has to team up with the dragon to protect it from dark wizards. Another idea is that the dragon is an outcast in the magical world and Harry befriends it, leading to a story about acceptance and friendship.
One idea could be a story where a young wizard discovers an ancient dragon egg in the Forbidden Forest. He secretly raises the dragon and they form an unbreakable bond. As the dragon grows, they face challenges from Hogwarts faculty who fear the dragon's power. But together, they prove that the dragon can be a force for good.