A really interesting concept in some Slytherin portrait fanfiction is that the portraits are sentient and have their own political system within the Slytherin common room. They vote on important matters regarding the house, such as which student should represent Slytherin in a school - wide competition. They also have their own rivalries and alliances among themselves, which adds a whole new layer of drama to the Slytherin house dynamic.
Some fanfics have the idea that the Slytherin portraits are actually portals to different times or places related to Slytherin's history. So a student could step through a portrait and end up in a secret Slytherin chamber from centuries ago. Also, there are stories where the portraits can change their appearance based on the current events in the Slytherin house, like if there's a big celebration or a time of crisis.
One unique aspect is the character development. Harry, as a Slytherin, has to deal with different values and expectations compared to being a Gryffindor. For example, he might rely more on cunning and strategy rather than pure courage. This changes his relationships with other characters too.
Well, it's unique because it flips the traditional view of Harry. Instead of being a Gryffindor, he's associated with Slytherin. This changes the dynamics of his relationships, like with Draco Malfoy, who he might be more allied with in these stories.
There are various plot ideas. Some fanfictions might explore the idea that the heir of Slytherin is not a single individual but a group of people who have been secretly working to change the reputation of Slytherin house. They could be working against dark wizards within the house who are trying to revive the old ways of pure - blood elitism. Or perhaps the heir has a connection to an ancient magic that is tied to Hogwarts itself, and in order to save the school from a new danger, they must unlock this magic. It could also be a story where the heir is in a love triangle with a Gryffindor and a Hufflepuff, adding a romantic element to the plot while still dealing with the challenges of being the heir of Slytherin.
Some unique ideas could be that baby Harry has a special bond with magical creatures from a very young age. For instance, he might be able to communicate with Hedwig even as a baby, through some kind of magical telepathy. This could set up a whole different dynamic in the story.
One idea could be a character who uses Dirty Harry - like tactics to deal with the Death Eaters. For instance, being extremely direct and fearless in the face of danger, much like Dirty Harry in his movies.
One unique aspect is the character development. Harry has to adapt to a different set of values and social dynamics. In Slytherin, he might be more cunning and politically aware. For example, he could use his new - found slytherin traits to outwit Voldemort in different ways than in the original story.
In some 'Harry Potter Harem' fanfictions, a unique idea is to have the 'harem' members be those who have been wronged by the dark side in different ways. They bond with Harry as they all strive for justice and a better wizarding world. For instance, a character whose family was destroyed by Death Eaters joins Harry's group. This creates a deep emotional connection among the group members and a strong motivation for their actions. It also gives a new perspective on the fight against evil in the Harry Potter universe, as they work together not just for Harry's sake but for their own and the world's.
Well, in some fanfictions, Loki might be interested in the Time - Turner device from the Harry Potter universe. He could try to use it for his own purposes, like going back in time to change certain events in the wizarding world to his advantage. Or perhaps Loki and Harry Potter get into a magical duel where Loki uses his Asgardian magic and Harry uses his wizarding spells. The contrast between their different forms of magic would be really interesting to explore in a fanfiction.
A unique idea could be that a Transformer is enchanted by a wizard to be able to use magic. So it becomes a sort of magical - mechanical hybrid. It could use spells like the wizards and also transform into different forms. For example, it could transform into a broom - like form to fly around Hogwarts.
A Harry Potter and Star Wars crossover would be really interesting. Picture Harry and his friends traveling through space in the Millennium Falcon, learning about the Force and using their magic in combination with Jedi skills to fight against a new dark threat that combines the power - hungry Sith and the dark wizards from the Potterverse.