A frequent trope is the 'orphanage abuse' trope. In many fanfictions, Harry endures some form of abuse or neglect in the orphanage, which adds to his trauma and his journey of self - discovery in the wizarding world. There's also the 'outsider' trope. Because he is raised in an orphanage, he is seen as an outsider not only in the Muggle world but also when he first enters the wizarding world, and this outsider status is often explored in detail in fanfictions.
One common trope is the 'lonely hero' trope. Harry is often depicted as a lonely figure in the orphanage, which makes his later discovery of the wizarding world even more impactful. Another is the 'hidden powers' trope. Some fanfictions suggest that Harry's time in the orphanage actually helped him develop some latent magical powers or abilities that are unique to him.
One plot idea could be that Harry discovers a hidden magic within the orphanage itself. Maybe there's a secret room that holds ancient spells or a connection to a long - forgotten wizarding family. Another idea is that the other orphans start to show signs of magic too, and Harry has to figure out how to protect them from the wrong kind of attention. Or perhaps the orphanage is under a curse, and Harry's presence there is the key to breaking it.
In the fanfiction, it could be interesting if Harry uses his magic to protect the other orphans from bullies. He might not fully understand his powers yet, but his instincts kick in. And then when he finally gets his Hogwarts letter, the other orphans are both sad to see him go but also excited for him, and he has to figure out how to leave the only home he's known while also being eager to enter the wizarding world.
One common trope is the 'alternate universe' where the story takes place in a different setting than the original books. For example, a modern-day muggle world with hidden wizarding elements. Another is the 'character redemption' trope, like Draco Malfoy being redeemed and becoming friends with Harry. And the 'power - up' trope is also seen, where a character discovers new and greater magical abilities.
One common theme is redemption. Often, the orphans in these stories have had difficult pasts, and through the love and care of Harry and Hermione at the orphanage, they find a new path in life.
One common theme is self - discovery. Harry has to figure out who he is without the influence of his parents. For example, in many such fanfictions, he might discover new magical abilities or a different heritage. Another theme is the struggle for acceptance. Since he's being raised by a 'top', there could be high expectations, and he has to strive to be accepted in this new environment.
Well, a typical trope is the main character having special abilities due to their reincarnation. This could be something like enhanced magic skills or the ability to understand ancient magic more easily. For instance, they might be able to cast spells without a wand more effectively than others. Another common thing is that they often have a different perspective on the Hogwarts houses. Instead of the usual biases, they might see the value in all houses and try to bridge the gaps between them. And, of course, there's the trope of falling in love with a character in a different way than in the original story. Maybe the reincarnated character ends up with someone who was just a minor character in the original.
One common theme is family. These fanfictions often explore the idea of what a real family could be for Harry, with Sirius as a loving father figure. Another theme is the exploration of Sirius's character. Writers like to show how he overcomes his past traumas to be a good parent to Harry.
One common trope could be the 'fish - out - of - water' situation. Harry Potter, being from his own magical world, would be out of place in the world of Elia Martell. And the 'lemon' aspect might be used to add an extra layer of complication or interest to this situation. For example, a love triangle might form between Harry, a character from Elia Martell's world, and another character, with the 'lemon' elements exploring the romantic and sexual tensions between them.
One interesting plot idea could be that Snape raises Harry with a strict but fair hand. He teaches Harry about the Dark Arts not to encourage him to use them, but to make him fully aware of the dangers. Harry might grow up with a more nuanced view of Snape from the start, and their relationship could be a mix of father - son dynamic and teacher - student. For example, Snape could train Harry in potions from a very young age, leading Harry to become a master of potions himself much earlier than in the original story.
Another plotline could involve how McGonagall deals with Harry's fame. Since she's very no - nonsense, she might shield Harry from the public eye more effectively. This could lead to a Harry who is less influenced by the adoration and more focused on his studies and personal growth.