Some fanfictions may focus on the magical or mythological aspects related to the pregnancy. Given that they are from a world of magic and gods, there could be unique elements such as prophecies about the child, or special powers that the unborn baby might possess. Writers might also explore how Sif's pregnancy affects her own strength and abilities as a warrior.
A lot of fanfictions might explore the relationship between Thor and Sif during this time. It could be about how their relationship deepens or changes. For example, they might have to learn to communicate better and support each other more. Also, the theme of protecting the unborn child from potential threats, whether from within Asgard or from other realms, could be common.
One common theme is the reaction of the Asgardian community. Since Thor and Sif are important figures, their pregnancy could have a big impact on the society. Another theme might be how they handle the challenges of impending parenthood while also dealing with their duties as warriors and protectors.
One common theme is unrequited love. Sometimes in fanfictions, Sif might be pining for Thor while he is oblivious or preoccupied with other things. Another theme could be adventure. They are both warriors, so stories often feature them going on quests together, fighting side by side against various enemies.
One common theme is the struggle with identity. Thor is used to being a strong warrior, and pregnancy changes that self - image. Another theme is the support system, like how his friends and family react. For example, Loki might be initially shocked but then become very protective.
One common theme could be the challenges the OC faces while being pregnant in a world related to Thor. It might involve dealing with Asgardian customs or Thor's responsibilities. Another theme could be the relationship development between Thor and the OC during this special time.
One common theme is the exploration of Thor's character in a new light. With him being pregnant, it might show his vulnerability and how he copes with the physical and emotional changes. Another theme could be the reactions of the other characters in the Marvel universe. How do they support or react to Thor in this situation?
You can try searching on fanfiction websites like Archive of Our Own (AO3). There are often a wide variety of fanfictions about different characters and scenarios. Just type in 'Thor and Sif pregnant' in the search bar and it should show relevant results.
Another plotline could be the challenges they face during the pregnancy. Since Loki has his mischievous nature and Sif is a strong - willed warrior, they might have different approaches to the pregnancy. There could be conflicts and then reconciliations as they figure out how to deal with the situation together. This can involve things like dealing with Asgardian traditions regarding pregnancy and childbirth.
Love and family are very common themes. Since Jane is pregnant, it explores how Thor and Jane's relationship deepens as they are about to become a family. It also often shows Thor's protectiveness towards Jane and the unborn child.
One common theme is redemption. Loki often has to redeem himself in the eyes of Sif for their love to develop. For example, in many fanfics, he might start off as a trickster causing trouble for Sif, but then he changes for the better.
Love and loyalty are also prevalent themes. Fanfictions show how their love for each other grows and endures despite the odds. They might face external threats or internal conflicts, but their loyalty to one another remains strong. This theme helps to create a more emotional and romantic aspect to the stories about their married life.
One common theme is friendship. The OC often becomes friends with the SIF characters and they go through various challenges together. For example, they might help each other prepare for a big concert in the SIF story.