For sure, Harry Potter is the main one. But in this fanfiction, there could be a local hermit who is actually a powerful wizard in disguise. He sees the potential in Harry and decides to train him in a different form of magic. Then there are Harry's pet animals on the farm. A magical dog, perhaps, that can sense danger and protect Harry. And there could be a young girl from the neighboring farm who becomes Harry's best friend and is the first to discover his magic, and together they embark on adventures around the farm and in the wizarding world.
Well, one possibility is that Harry grows up learning all about farming chores. He might use magic to make the crops grow faster or to tend to the animals in a unique way. Maybe he discovers some magical creatures living in the farm's outskirts that are related to the wizarding world but unknown to most wizards.
Obviously, Harry Potter himself would be the central character. But there could be a mafia boss who takes him in, maybe someone with a lot of power in the wizarding underworld. And there might be some henchmen characters who act as Harry's guardians or trainers in this new, dark world.
In this fanfiction, Harry is the main character for sure. There could be a trapeze artist who is secretly a witch or wizard from another land and helps Harry discover more about his own powers. And the circus's animal trainer, who has a special bond with the magical animals in the circus, could also play an important role in Harry's life, teaching him about the connection between magic and the natural world of the circus animals.
Obviously, Harry would be the main character. But there could be new characters like a Russian wizard mentor who teaches Harry about the unique Russian magic. Another could be a young Russian witch who becomes Harry's best friend and helps him adapt to the Russian wizarding world.
Obviously, Harry Potter himself would be the main character. But there could be new characters like his Chinese friends. For example, a girl named Mei who is an expert in Chinese calligraphy magic.
Harry Potter is the main focus, of course. But the dragon would play a crucial role. It could be a dragon with a special backstory, like it was once a guardian of some great magic and now it passes that knowledge on to Harry. Other characters could include some of Harry's friends from Hogwarts. They might be initially scared of Harry because of his dragon - like behavior but later come to understand him. And there could be some villains from the original story who try to take advantage of Harry's unique situation.
Definitely Sam and Dean Winchester. They would be like his surrogate brothers or mentors. Then there's Castiel, the angel. He could have some interesting interactions with Harry, perhaps being intrigued by his magic. Bobby Singer could also be there, guiding Harry in the ways of hunting.
Obviously, Harry Potter would be the central character. But the Addams family members like Gomez and Morticia would play crucial roles as his new family. Wednesday Addams could be an interesting character in relation to Harry. She has her own dark and mysterious side, and she might either be a great friend or a bit of a rival to Harry in this new setting.
For this fanfiction, Harry Potter is the main focus, but from Fairy Tail, Makarov Dreyar could be a key character. As the guild master, he could be like a father figure to Harry, guiding him in his growth and development in the Fairy Tail world. Wendy Marvell could also be a main character. Her healing magic and gentle nature could be a great influence on Harry. And Happy, the blue flying cat, could be Harry's sidekick, adding some comic relief and also helping him out in various situations with his unique abilities.
One possible main character could be a Martian elder who takes Harry Potter under their wing and helps raise him. This Martian elder could have special knowledge about the planet and its hidden magic that they pass on to Harry.