In these fanfics, the theme of adaptation is quite common. Harry has to adapt to his new identity, whether it's a new name, a new magical ability, or a new social standing. Another theme is the exploration of different magical cultures. If his identity is changed in a way that he's associated with a different group, like a foreign wizarding community, it delves into different magical practices. And identity crisis is also a key theme. Harry may struggle with who he is now compared to who he was supposed to be in the original story.
One idea could be that Harry has an alternate identity as a Muggle detective. He uses his magical skills secretly to solve cases that have a magical element but are disguised in the Muggle world. For example, he might be investigating a series of strange disappearances that are actually the work of a dark wizard trying to gather ingredients for a powerful spell.
I really like 'A Different Harry Potter'. In this fanfic, Harry is raised by a different family, which gives him a whole new identity. He has different values and skills compared to the original Harry. Another interesting one is 'Harry Potter: The Time - Traveler'. Harry goes back in time and has to assume a new identity to avoid disrupting the past too much. It's a fascinating read as it weaves in elements of time - travel and alternate identities.
His appearance and behavior in the alternate identity should be different yet still recognizable as Harry. If he's an undercover Auror in a different country, he might change his hair color with a simple spell, but his determination and quick thinking would still be there. His speech pattern could also change slightly to fit the new identity. He might use different magical tools or spells that are common in that region but still rely on his basic Hogwarts training at the core. This combination of change and familiarity makes the alternate identity believable in the context of a fanfic.
Well, Hermione is often depicted in different ways in these fanfics. In some alternate universes, she could be a powerful dark witch instead of the studious and good - hearted character we know. Ron might be a super - confident and arrogant character rather than the sometimes insecure boy in the original story. Also, Snape could be a completely different person. He could be a jolly and friendly teacher rather than the brooding and complex one we are used to.
In an alternate dimension, the main antagonist could be a dark entity that has emerged from the very fabric of the dementions themselves. This entity could be using the Dementors as its minions, controlling them to do its bidding. It would be a powerful and mysterious foe, and Harry would have to discover its true nature and weaknesses in order to defeat it.
One interesting idea could be that Harry decides not to defeat Voldemort in a traditional battle. Instead, he uses a powerful spell of love and redemption to turn Voldemort back to his original self, Tom Riddle, a lost and confused boy. This would completely change the whole dark - vs - light dynamic of the story.
Well, in some Harry Potter alternate reality fanfics, the houses at Hogwarts are sorted differently. For example, instead of the Sorting Hat choosing based on certain traits, students are sorted randomly. This completely changes the social structure within the school. Also, there are fanfics where magic works in a different way. Maybe spells require a different type of wand movement or incantation. It makes for a really fresh take on the magic we know from the original books.
Hermione Granger often remains popular. In alternate fics, she might be portrayed as an even more powerful witch, leading new magical research or changing the way magic is taught. Harry Potter himself is also a common focus, maybe with different powers or a different role in the wizarding world.
Well, one interesting concept could be a different Sorting system in Hogwarts. Maybe instead of the traditional four houses, there are new ones based on different magical abilities. Another could be an alternate version of the Ministry of Magic, with different laws and regulations regarding magic use.