There's also a possibility of her allying with some of the more neutral houses. Houses that were tired of the constant fighting between the big players. Her daughter could offer them stability and protection in exchange for their loyalty. She could present herself as a new hope for a more peaceful Westeros, which might attract these houses to her side.
Sansa Stark could be an interesting pairing. It could be a story of two strong - willed women from opposing sides. They could either become bitter enemies or, in a more creative take, find common ground and form an unexpected alliance. Also, Margaery Tyrell is a great character to pair with Cersei. Their power struggle in the show was fascinating, and fanfiction could take it in new directions, like Margaery actually befriending Cersei and showing her a different way to rule.
One possible storyline could be that Cersei's daughter rebels against her mother's tyrannical ways. She might see the destruction Cersei has caused and decides to take a different path, perhaps allying with the Starks to bring peace to Westeros.
Yes, there are quite a few out there. Some focus on how Cersei's pregnancy would change her power dynamics in King's Landing. For example, in some fanfictions, her pregnancy makes her more vulnerable to political attacks as her enemies see an opportunity to undermine her while she is in a physically weaker state due to pregnancy. However, the quality of these fanfictions can vary greatly.
There's also 'Jaime and Cersei: The Unwritten Chapters'. This fanfiction fills in the gaps between the events shown in the show. It gives more in - depth exploration of their emotional states, especially during the times when they were separated, and how they coped with the challenges to their relationship.
One interesting plotline could be an alternate universe where Jaime decides to fully turn against Cersei much earlier. He might expose her secrets to save the realm from her tyranny, leading to a complex power struggle within King's Landing.
One common theme is the struggle for power. Even while pregnant, Cersei is a character who desires power. So in fanfiction, she may be trying to secure the throne for her unborn child. Another theme could be betrayal. Since Cersei has many enemies, there might be plots to harm her or her baby, leading to stories of betrayal and backstabbing.
In fanfiction, Sansa and Cersei's relationship can be complex. Sansa often starts as a naive girl in Cersei's presence. Cersei sees Sansa as a tool or a threat at different times. Sometimes, fanfiction might explore a scenario where Sansa grows to outwit Cersei, using the lessons she's learned from her difficult experiences in King's Landing. Their relationship is a rich area for fanfiction writers to delve into, as they are two very different yet strong - willed female characters in the Game of Thrones universe.
One interesting Cersei fanfiction could be about her early days in King's Landing before all the chaos really began. It might explore her relationship with her father in more depth, showing how he influenced her rise to power. Another could be a 'what if' scenario where she forms an unlikely alliance with a character she normally despises, like Daenerys. They could team up against a common enemy, perhaps the Night King, and in the process, Cersei has to confront her own prejudices and power - hungry nature.
In some fanfiction, Jaime's character might develop into a more remorseful figure. His relationship with Cersei could be a source of internal conflict, and he could start to question his loyalty to her more deeply, leading to a change in his actions and decisions.