I really like 'Klaus and the Unlikely Companion'. In this fanfiction, the OC is a witch who crosses paths with Klaus. What makes it stand out is the way it portrays Klaus's vulnerability around the OC. It shows a different side of him that we don't often see in the show. The plot twists are also quite engaging.
The plot is crucial. It should be engaging and not just a rehash of the show's storylines. Maybe it could involve a new supernatural threat that Klaus and the OC have to face together. This gives an opportunity for character growth and development of their relationship. Additionally, the writing style matters. It should be easy to read and flow well, with good dialogue that captures the essence of the characters.
There are many interesting fanfictions on this topic. Some might focus on how they deal with the pregnancy in the dangerous world of vampires and werewolves. For example, they could be facing threats from other supernatural beings who see their unborn child as a threat or a powerful asset.
Another theme is protection. Given the dangerous nature of their world, protecting the unborn child from various threats is often a central plot point. Enemies might try to harm the baby because of its potential power or to get revenge on Caroline and Klaus.
I'm not sure about a specific title that stands out above all others for TVD Klaus gay fanfic. However, if you search on platforms like Wattpad, you might come across some interesting ones. Some fanfics might focus on Klaus's character development as a gay vampire in relation to other characters from the show. You could also try looking at Tumblr blogs dedicated to Vampire Diaries fanfic. They often share and recommend good gay fanfics involving Klaus.
First, you need to really understand the character of Klaus from TVD. Know his personality traits, his backstory, and his relationships within the show. Then, create a male character that would be an interesting match for him. You can start with a simple plot, like how they meet and what draws them together. For example, it could be because of a shared goal or a mysterious connection. Also, don't be afraid to add your own unique twists to the Vampire Diaries lore.
Well, a possible plot is that Elena's pregnancy is the result of a spell gone wrong. Klaus, despite his initial shock, decides to stand by her. This could lead to a series of events where they have to fight off those who see the baby as a threat. It could also explore how Elena deals with the physical and emotional changes of pregnancy while being in a rather strange relationship with Klaus. And the baby might have some unique abilities that are both a blessing and a curse.
Their relationship would likely become more complex. Klaus, who is used to being in control, might become more possessive yet also more tender towards Elena. Elena, on her part, would have to rely on Klaus more, which could create a strange bond between them. They would have to learn to trust each other in a whole new way as they are now responsible for the unborn child.
The key is to find common ground. For example, both shows deal with the supernatural. So, a plot where a powerful supernatural entity threatens both the world of Supernatural and Mystic Falls would bring the characters together. Sam's knowledge of lore could combine with Bonnie's magic skills to fight this entity.