You can try fanfiction websites like Archive of Our Own (AO3). It has a vast collection of fanfictions on various topics, including Elijah and Katherine's love stories. Another place could be Fanfiction.net. Just search for the relevant tags like 'Elijah' and 'Katherine' along with 'love' to find the specific stories you're interested in.
One popular story might be 'Eternal Love of Elijah and Katherine'. It could explore their relationship in a different timeline, perhaps where they meet under different circumstances and their love blossoms in a more peaceful setting. Another could be 'Katherine's Redemption through Elijah's Love', which may focus on Katherine's character development as she is loved by Elijah.
The main characters are clearly Elijah and Katherine. They are the central focus of this fanfiction, especially since the title mentions them directly and the pregnancy is related to them.
Well, it could be about how they deal with the unexpected pregnancy. Maybe they struggle to accept it at first, then gradually come to terms and start preparing for the baby.
The Originals' enemies, like the werewolves, could be antagonists. They might see the baby as a symbol of the vampires' growth and power and try to harm it. Also, some of the other vampire factions who are against the Mikaelsons could target the baby to get back at Elijah and Katherine.
Their relationship would likely become more protective. Elijah would be extremely protective of Katherine and the unborn child. He might become more possessive in a way, not wanting to let any harm come their way.
One idea could be that the baby has some sort of special power. Since Elijah is a powerful vampire and Katherine has her own unique charm and skills, their baby might inherit something extraordinary. Maybe the baby can control the minds of vampires or has an uncanny ability to sense danger.
One interesting fanfiction could be about Elijah trying to redeem Katherine. Maybe he sees a side of her that others don't, and he attempts to guide her towards a more positive path. It could involve them traveling together and facing various challenges from the vampire world.
Some popular fanfiction platforms like Archive of Our Own have search filters. You can search for Vampire Diaries, Elijah and Katherine - related fanfictions and then check out the authors of the stories that you like the most. They are likely to be good writers in this area. For example, if a story has a really engaging plot and well - developed characters, chances are the writer is skilled at writing about these two characters.
One idea could be that they face challenges from the supernatural community due to their unborn child's potential power. The other vampires or witches might see the baby as a threat or a valuable asset. Another plot could be them preparing for the arrival in a world full of danger, like building a safe haven and gathering allies.