One common theme is romance. Writers often pair female Elijah with other characters, either from the show or original characters they create. Another theme is power struggles. Given Elijah's powerful nature in the show, in fanfiction, a female Elijah might also face challenges related to power within the vampire - werewolf - witch world. Family dynamics is also a theme, exploring how she interacts with her family members in new and different ways.
A popular theme is redemption. Maybe female Elijah has made some mistakes in the past and is on a journey to redeem herself. Alternate universes are also quite common. For example, a fanfic might be set in a world where the rules of the supernatural are different, and female Elijah has to adapt. Transformation is another theme, like her changing from a 'bad' character to a 'good' one or vice versa over the course of the story.
A lot of Elijah Mikaelson daughter fanfictions deal with the theme of redemption. Maybe the Mikaelson family has done some bad things in the past, and the daughter tries to make up for it or change the family's reputation. There's also the theme of discovery, like her exploring the secrets of her family's past and her own abilities.
One common theme is love and loss. Elijah often experiences heartbreak in these fanfictions, whether it's the loss of a loved one or the end of a relationship. This theme helps to drive the emotional pain he endures.
One common theme is redemption. Elijah often has a past full of darkness, and through love, he tries to find redemption. For example, in many fanfics, his love for a certain character makes him want to be a better person.
One common theme is the clash of their two different vampire worlds. Bella is from the Twilight world with its own set of vampire rules, and Elijah is from The Vampire Diaries universe with different lore. Another theme is the struggle for acceptance within their respective families and communities. Since they are mates, they have to find a way to make their relationship work despite potential opposition.
There are often themes related to power dynamics as well. Given that Elijah is a powerful vampire, his relationships in gay fanfics can be influenced by this. He might be in a relationship with a less powerful character, and this creates a certain power imbalance that can lead to interesting storylines. Or he could be in a relationship with someone of equal power, and they have to navigate their relationship while also dealing with their powerful positions in the vampire hierarchy.
One common theme is the forbidden love aspect. Given Elijah's complex vampire family and their world full of danger and secrets, a relationship with a human reader (if that's the case) can be seen as forbidden. Another theme is protection. Elijah is often portrayed as very protective of the reader.
There are many amazing Elijah Mikaelson fanfictions. 'Elijah's Legacy' is a fanfic that looks at how he tries to leave a positive mark on the world despite his past deeds. It has some great character development. 'The Dark Side of Elijah' is interesting too as it explores the parts of him that he tries to hide from others. And 'Elijah and the New Beginning' is a story about him starting anew, away from all the chaos of his family and past.
A really interesting fanfiction could be set in an alternate universe where the rules of the Vampire Diaries and whatever world Lemon is from are combined. Elijah and Lemon are brought together by a prophecy, and they must figure out how to fulfill it while dealing with their growing feelings for each other.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a vast collection of fanfics. Just search for 'female Elijah Mikaelson' in the search bar, and you'll get a list of relevant stories. Another option is Fanfiction.net, which also has a lot of fan-created content related to various characters, including this one.
Elijah Mikaelson is a complex and alluring character. Fanfiction allows fans to explore different aspects of his personality. His sense of loyalty and his struggle between his family's dark deeds and his own moral code make for great storytelling. Also, his relationships, like with Klaus and Elena, can be further developed in fanfiction.