There are indeed some great ones. A lot of fanfiction writers like to delve into the concept of Edward as a vampire king because it allows for a lot of creativity. They can explore how his vampiric powers might be enhanced in a leadership position, how he deals with the politics among different vampire clans, and also how his love for Bella might be affected or even strengthened in this new scenario.
Power and leadership are common themes. Writers often explore how Edward would handle the responsibilities of being a king, like making decisions for the vampire community.
One interesting aspect could be how their relationship dynamics change. In the original, Edward was the vampire and Bella was the human, so reversing their roles might lead to a different power dynamic. For example, Bella as a vampire would have more physical strength and speed, which could make her more protective of Edward. Also, Edward as a human might struggle with his mortality compared to Bella's immortality, creating new tensions and storylines in the fanfiction.
Edward in Twilight fanfiction is typically depicted as having an intense internal struggle. His love for the human girl is always at odds with his vampire instincts. He may be more conflicted in fanfiction than in the original books, as authors explore different scenarios. For example, some fanfics might show him having to choose between his family and his love in a more extreme way. Also, his relationship with other vampires can be further developed in fanfiction, showing his loyalty or lack thereof in different situations.
One great fanfiction could be where Edward and Bella's relationship is explored more deeply in a different vampire society setting. For example, they might be in a vampire clan that has unique rules about human - vampire relationships.
A common theme is the 'what - ifs'. What if Bella had chosen Jacob instead? Fanfictions often explore this alternative storyline and how it would affect the vampire - human relations in Forks. It can be really interesting to see how the characters develop in this different scenario.
One of the main characters might be Alice. Her ability to see the future could be crucial in helping Edward navigate the political and dangerous situations in his role as king. Also, Jasper could be there. His experience in combat and control of emotions could be useful for Edward's rule. And then there's Rosalie, who might have her own opinions on how Edward should run the kingdom and could be a source of conflict or support depending on the story.
The character interactions are also unique. You get to see how the Twilight characters like Bella or Edward Cullen might interact with a figure like King Edward. Maybe they would be in awe of his royalty or he might be intrigued by their supernatural abilities. It opens up a whole new world of relationships to explore in fanfiction.
His mystery. In fanfiction, like in the original Twilight, Edward is a very mysterious character. He has a long past as a vampire prince which is often explored in fanfictions, making readers want to uncover more about him.
Well, for one, the whole concept of their courtship would be different. Since Bella is now the vampire, she would be the one with the enhanced senses and abilities. She might be more forward in the relationship as she doesn't have the same insecurities as she did as a human. Edward, on the other hand, might be more hesitant and in awe of Bella's newfound power.