One common theme is redemption. Klaus is often depicted as seeking redemption through his relationship with Bonnie. Another theme is the power dynamic. Bonnie has her own powerful magic, and Klaus is a powerful hybrid, and their powers play a role in how they interact. For example, they might be in a situation where they need to combine their powers.
A common theme is the exploration of their individual traumas. Bonnie has faced a lot in her life, and Klaus has his own tortured past. Fanfics often show how they help each other heal. Also, the theme of loyalty comes up. When they form a relationship, they have to decide where their loyalties lie, whether it's with their old friends and family or with each other. This creates a lot of interesting conflict and plot development.
One common theme is the power dynamic. Bonnie has her own strong magic and Klaus is a powerful original vampire. Their relationship often plays around with who has the upper hand. For example, in some fanfics, they use their powers against each other at first and then learn to cooperate.
Another theme is the protection of the unborn child. Given the dangerous supernatural world they live in, both Bonnie and Klaus are usually depicted as being extremely protective. They will go to great lengths to keep their baby safe from all the threats out there.
One common theme is friendship. Many Bonnie fanfics focus on Bonnie's relationships with her friends and how they support each other through various challenges.
Friendship is a common theme. Writers often show how Bonnie and Toy Bonnie become friends despite their differences. Maybe Bonnie is the more traditional character and Toy Bonnie is the new addition, and they learn to get along.
One common theme is family. Since Klaus comes from a complex family in the Vampire Diaries universe, many fanfics about baby Klaus explore his family relationships. Another theme is his emerging powers. Writers often like to play with how his powers might have started to show when he was a baby.
A common theme is the clash of two different worlds. Since Hermione is from the wizarding world of 'Harry Potter' and Klaus is from the vampire world of 'The Vampire Diaries', there's often exploration of how their different powers and cultures interact.
One common theme is the power dynamic. Klaus is often a powerful character, and the relationship with the reader explores how they interact with that power. For example, the reader might be in a position of vulnerability at first but then find their own strength.
Love is a very common theme. Most fanfics explore the deep love between Bonnie and Enzo. Another theme is sacrifice. They are often in situations where they have to sacrifice something for each other or for the greater good. Also, the theme of redemption can be found in some, where they are trying to redeem themselves from past mistakes.
One common theme is power. Bonnie is a powerful witch, and many fanfics explore her powers further, like how she can gain new ones or master existing ones. Another is friendship. Since she has complex relationships in the show, fanfics often deal with her mending or strengthening friendships.
One common theme is self - discovery. Bonnie Sinclair often embarks on a journey where she learns more about herself. Another theme could be friendship, as she forms bonds with other characters in the fanfics.