One possible plotline could be Yor dealing with her pregnancy while still trying to keep her assassin identity a secret from her family. She might struggle with the physical and emotional changes that come with pregnancy while also maintaining her cover.
There might not be a lot of publicly known 'pregnant Yor Forger fanfic' readily available. You could also try joining some Spy x Family fan communities. There, fans often share their own creations or know where to find unique fanfics. It's possible that someone in the community has written or knows of such a story.
A more complex plot could be about Yor dealing with the physical and emotional changes during pregnancy in a world full of danger. She might have to rely on her own strength more than ever, and her pregnancy could even be a target for her enemies, leading to a high - stakes story.
One great fanfiction could be where Loid and Yor's first kiss is a result of a near - miss mission. They think they might lose each other and in a moment of intense emotion, they share a kiss. It's a sweet and unexpected moment that deepens their connection.