One common theme is the idea of redemption. Loki often has a journey of self - discovery and redemption, and Natasha can be a part of that. Another is the clash of different worlds. Loki from Asgard and Natasha from Earth have very different backgrounds.
One common theme is the clash of personalities. Loki is often depicted as a complex and somewhat devious character, while Natasha is very shrewd and calculating. Their interactions usually involve a lot of mental sparring. Another theme is redemption. Sometimes Loki is on a path to redeem himself and Natasha plays a part in that journey. For example, she might be the one to believe in his potential for good when others don't.
One common theme is adventure. Given their roles in the Marvel universe as heroes, many fanfics put them in exciting new adventures together. Another theme is romance, of course, exploring their relationship in different ways, like a slow - burn love story.
One common theme is the exploration of their mutual understanding. Given their complex pasts, fanfics often show how they can see through each other's facades. For example, in many stories, Natasha is able to calm Bruce when he's on the verge of losing control.
One common theme is the age - gap dynamic. Given that Peter is much younger than Natasha, it creates an interesting contrast in their relationship. Another theme is mentorship. Natasha can often be portrayed as a mentor figure to Peter, guiding him in the ways of the superhero world.
A common theme is trust. Since Natasha often has a guarded nature, the fanfics usually explore how she gradually trusts the reader. Another theme is mutual understanding. The reader has to understand Natasha's complex past and her role as an agent. Love and attraction are also very common themes as the relationship between the two develops.
Often, there's a theme of family and legacy. The baby could be seen as a new hope or a potential change for the future of Asgard or their family. And the whole situation might force Thor and Loki to re - evaluate their places in their family and the world. It's also common to see themes of sacrifice and love, as they face difficulties together due to Loki's pregnancy and they have to make choices to protect each other and the unborn child.
One common theme could be redemption. After experiencing abuse, Loki might be on a journey to redeem himself or find a way to heal. Another theme could be power dynamics. The abuse might be related to power imbalances between Loki and Thor, which can be explored in different ways. And also, the theme of forgiveness could play a role, either Loki seeking forgiveness from Thor or vice versa.
Redemption is also a theme. Given Natasha's past as an assassin, some fanfics have the Reader be a part of Natasha's journey towards redemption. It could be that the Reader's positive influence helps Natasha come to terms with her past actions and strive to be a better person. And of course, action and adventure are often part of it too, as they are both likely to be involved in dangerous situations in the Marvel universe.
Another theme is redemption. Sometimes Loki is in a state where he needs to redeem himself and the OC becomes a part of that journey. They help him see things in a new light and grow as a character. It makes for a very engaging read.
Power is a common theme. Thanos is extremely powerful and Loki is always seeking more power, so fanfics often explore how they interact in terms of power - whether it's a power struggle or a shared pursuit of power.