I'm not sure of a specific one off - hand, but a good plot could be where Jeremy's Law is the only way to stop a powerful dark wizard. The wizard has found a loophole in all the existing magical laws, but Jeremy's Law has a clause that can be used against him. The main characters then have to search for all the details about this law and find a way to use it effectively.
Imagine a fanfiction where Jeremy's Law is a prophecy - like law. It was foretold that when the wizarding world is in its darkest hour, Jeremy's Law will be the guiding light. So when a great evil starts to spread across the wizarding world, the characters have to figure out what Jeremy's Law actually means and how to use it to save the day. It could involve a race against time, as the evil is growing stronger every day, and they have to unlock the secrets of this law before it's too late.
There could be a fanfiction where a selkie has been cursed and the only way to break the curse is through a complex spell that requires knowledge from both the selkie world and the wizarding world of Harry Potter. The plot could involve the characters traveling between different magical realms, gathering ingredients, and facing various challenges along the way. This would create a really engaging and complex plot that ties the two worlds together.
One more is 'Among the Durmstrang'. In this fanfiction, the plot focuses on a group of Durmstrang students who come to Hogwarts for a tournament. But there is an underlying plot of a conspiracy within Durmstrang that the main characters gradually uncover. It's a very engaging read with a well - developed plot.
There's a fanfiction called 'Naga and the Dark Prophecy'. The plot is quite strong as it involves a Naga who discovers a dark prophecy that concerns the future of the wizarding world. The Naga then teams up with Harry Potter to try and prevent the prophecy from coming true. The story is filled with twists and turns as they battle against powerful dark wizards who are also interested in the prophecy. It also explores the Naga's own motives and backstory in relation to the prophecy.
A fanfiction titled 'Belgher's Quest with Harry Potter' has a strong plot. In it, Belgher discovers a prophecy that involves both of them and a powerful dark magic artifact. They must journey across different magical locations, from the Forbidden Forest to the hidden chambers of Hogwarts, to stop the artifact from falling into the wrong hands. Along the way, they face numerous challenges and encounter old enemies and new allies.
One interesting fanfiction could be about how Jeremy's Law might affect the magical world in Harry Potter. For example, it could explore if there are new rules in Hogwarts based on Jeremy's Law that the students have to follow. It might change the way Quidditch is played or how students interact with magical creatures.
Yes, there's a fanfiction where the Revelio Zauber is the key to solving a mystery about a series of disappearances in the wizarding world. The main character uses the spell to gradually uncover clues that lead to a powerful dark force that has been operating in secret. It has a really strong plot full of twists and turns.
Another one is 'Magic and Monsters'. Here, the plot is centered around a new kind of monster that is attracted to the magic in Hogwarts. The Supernatural characters come to investigate, and they end up getting caught in a web of Hogwarts politics and magical intrigue. The author does a great job of building the story, slowly revealing the mystery behind the monster and how it relates to both universes, all while the characters are growing and changing in this new and strange environment.
I would recommend 'Blood and Magic: The Blood Bender's Tale'. It has a really strong plot that revolves around a Blood Bender who is actually a descendant of an ancient magical bloodline. The story unfolds as they try to uncover the secrets of their bloodline while also dealing with the normal Hogwarts drama and the threat of dark forces. There are many twists and turns, like when they find out that their blood power is linked to an ancient prophecy that could change the fate of the wizarding world.
There might be a fanfiction where the panther animagus is an outcast in the wizarding world because of their form. They then get drawn into Harry Potter's fight against the dark forces. As the story progresses, the panther animagus discovers their true potential and their role in the grand scheme of things. This would be a strong plot as it involves character development, a sense of belonging, and the overarching battle between good and evil in the Harry Potter world.
There is a fanfiction called 'Red Lion's Legacy'. It has a strong plot where the Red Lion is a guardian of a magical realm that is slowly being corrupted by dark magic. Harry and his friends discover this and must work with the Red Lion to cleanse the realm and prevent the spread of the dark magic to Hogwarts and the rest of the wizarding world. It has great character development and a complex plot structure.