One interesting 'Harry Greenwood' 'Charmed' fanfiction could be one where he uses his unique charm to solve a mystery within the Charmed universe. Maybe he teams up with the Halliwell sisters to fight a new kind of dark magic.
You can start by looking on popular fanfiction websites such as Archive of Our Own (AO3). It has a large collection of fanfictions from various fandoms, so there's a good chance you'll find some 'Harry Greenwood' 'Charmed' fanfictions there.
There could be a really interesting fanfiction where the magical worlds of Charmed and Harry Potter collide with Harry and Maggie. Maybe they team up to fight a new kind of dark magic that threatens both their realms. They could each bring their unique magical abilities to the table. Harry with his wizardry from Hogwarts and Maggie with her powers as a Charmed one.
One common theme is the exploration of different magical powers. Since both universes have their own unique magical elements, fanfictions often focus on how these powers interact. For example, the spell - casting in Harry Potter and the power of three in Charmed.
Well, there are several common themes. First, the theme of growth. Both Harry and Macy grow as characters, whether it's in their magical skills or in their emotional understanding. Second, the theme of mystery. Many fanfics involve them solving some sort of mystery, whether it's about a strange magical occurrence or an ancient prophecy. And finally, the theme of connection. Their connection, whether it's platonic or romantic, is a key element. It's what drives the story forward in most cases, as they rely on this connection to get through difficult situations in the magical world.
Well, they might meet in a magical crossroads. Harry could be on a mission related to the wizarding world and Maggie could be dealing with a demon in her Charmed world. And they just happen to cross paths. They'd be initially confused but then intrigued by each other's powers.
One interesting crossover could be the use of spells. For example, a Charmed one might learn a spell from the Harry Potter world like the Patronus charm. It could be used in a new and different way in the Charmed universe, perhaps to fight a new type of demon that is vulnerable to positive magic like a Patronus.
Well, in such a fanfiction, Harry might grow up with different magical abilities. Since the Charmed Ones have their own unique powers, he could learn a whole new way of using magic compared to what he would have learned at Hogwarts. Maybe he'd be more attuned to potion - making in a charmed way, or his defensive magic could be a blend of Hogwarts spells and Charmed - style combat magic.
Often, in such fanfiction, new original characters are introduced. They could be the ones who created the charmed lemon in the first place. But it's also possible that characters like Dumbledore could play a significant role. He might know more about the charmed lemon than he lets on and be guiding the other characters from behind the scenes. Neville could also be a main character, using his skills with plants to take care of the charmed lemon or study it.
One popular trope is the 'crossover' where characters from Charmed and Harry Potter universes interact. For example, the Halliwell sisters might meet Harry, Hermione and Ron. Another is the 'power transfer' trope, like a Charmed one getting some magical ability from the Harry Potter world or vice versa. And the 'hidden relation' trope is also seen, such as a character from one universe being related to a character in the other in some unexpected way.