One great fanfic could be 'Cole's Redemption with the Niece'. In it, Cole might find a new purpose in protecting the Charmed niece. It could show their unique bond as he uses his powers for good in relation to her.
You can start by looking on fanfiction - dedicated websites like Archive of Our Own (AO3). There are likely to be a good number of stories there tagged with relevant keywords like 'Cole Turner' and 'Charmed Niece'.
A common theme is family. Since Cole and his niece are related, it often explores the family dynamic within the Charmed world. It might show how family ties can be both a strength and a source of conflict.
One popular 'Charmed Cole Niece' fanfic could be 'The Unlikely Bond'. It explores the complex relationship between Cole and his niece in a really interesting way, with lots of emotional moments and plot twists.
One great 'Charmed Elizabeth Turner' fanfic is 'The Magical Journey of Elizabeth'. It delves deep into her character's backstory and how she discovers her powers within the Charmed universe. It's full of interesting plot twists and character development.
Yes, there might be. The 'Charmed' fandom has a wide variety of fanfics exploring different relationships and emotions. Cole and Phoebe's relationship was complex in the show, with a lot of love but also moments of hate and hurt. So it's likely that some fans have delved into writing about those darker aspects in fanfic form.
In a 'Sister Charmed' fanfic involving Cole and Elizabeth, the author might be reimagining the characters' personalities. For example, Cole could be more heroic in his interactions with Elizabeth, or Elizabeth could have some unique powers that Cole is drawn to. This can add new layers to the existing 'Sister Charmed' lore.
Cole might be initially hesitant. He has a complicated relationship with his mother. He could be suspicious of her motives, especially if he has grown used to his new life away from her influence.
For a 'Charmed Elizabeth Turner' fanfic to be good, it should explore her relationships. Whether it's her friendship with other witches or her romantic interests, these relationships can add depth to the story. It should also have some sort of conflict, like an internal struggle within Elizabeth herself or an external threat to the Charmed world that she has to face.