Hermione Granger could be one of the main witches. She's extremely intelligent and powerful, and in the fanfiction, she might be involved in some secret magical research or adventures.
Since it's a fanfic, the main characters could be original witches created by the author. Or it might focus on some of the known witches from the Harry Potter series like Hermione (although she's a witch - wizard hybrid in a way), and expand on their stories in relation to the secret.
Harry Potter would likely be one of the main characters, as it is related to the Harry Potter universe. And of course, the witches in the coven would be main characters too. Maybe there's a head witch who leads the coven and plays a significant role in the story.
I'm not sure specifically as it's a fanfic. It might be about some secret that the witches in the Harry Potter world hold. Maybe it could involve a hidden magic, a clandestine society of witches, or a mystery related to a particular witch character.
One interesting aspect could be the exploration of the witches' unique magic that might not be fully shown in the original series. For example, they could have secret spells or ways of using magic related to their femininity.
Well, in secret fanfic, witches often have unique magical abilities that are not fully explored in the original books. For example, they might be able to perform rare spells related to nature or mind - reading. Some fanfics might show witches with a deeper connection to the magical creatures, like being able to communicate with them on a more profound level. It gives a new perspective on the witches in the Harry Potter universe.
There's 'The Witches of Hogwarts Unveiled' which delves deep into the lives of the witches at Hogwarts. It shows their secret meetings and the spells they practice away from the prying eyes of the professors. Another one is 'Secret Societies of Witchcraft in Harry Potter World' which focuses on different groups of witches and their unique magical practices.
Glinda the Good Witch is very popular. People love her for her kindness and her role as a helper in 'The Wizard of Oz'. In the 'Charmed' series, the Halliwell sisters are popular as they show strong female characters using magic to protect the world. Also, the White Witch from 'The Chronicles of Narnia' is popular because of the epic story she is a part of and her menacing presence in Narnia.
I don't recommend fanfiction with such a disturbing concept as 'Harry Potter enslaves witches'. The 'Harry Potter' series promotes values like friendship, courage, and equality, and this idea goes against the positive spirit of the original work.
Family heritage could also be a theme. Witches often pass down their powers and knowledge through generations, so the novel may delve into how family ties play a role in the world of witches, whether it's about the bond between mothers and daughters or the continuation of magical traditions within a family.
The main appeal is its rich and immersive world-building, along with complex and compelling characters.