Well, it really depends on what you consider 'good' in a 'Takashi x Saeko lemon fanfiction'. Some people like stories with a lot of character development, while others might be more interested in the romantic or steamy scenes. You can start by looking at the top - rated or most - reviewed fanfictions on popular fanfic sites. Also, be aware that different platforms have different rules regarding the content of fanfictions, so you might need to search around a bit to find exactly what you're looking for.
Survival scenarios are also quite common if these characters are from a post - apocalyptic or action - oriented anime. They might have to rely on each other in dangerous situations, which can bring out different aspects of their relationships. For example, Takashi might have to protect Rei and Saeko from threats, and this can strengthen or test their bond.
One popular takashi x saeko fanfiction might be 'A New Beginning'. It shows their relationship evolving in a post - apocalyptic world. They face challenges together and their bond deepens as they rely on each other for survival.
You can try websites like FanFiction.net. It has a large collection of fanfictions from various fandoms, and you're likely to find some good takashi x saeko ones there.
One popular saeko x takashi fanfiction could be 'A New Beginning'. It might explore their relationship in a post - apocalyptic world, showing how they rely on each other and gradually fall in love. Another could be 'Together Against All Odds' which may focus on their adventures and how their bond strengthens during difficult times.
One possible scenario in this fanfiction could be that Takashi and Saeko's pregnancy brings out new sides of their characters. Takashi might become more protective, constantly worrying about Saeko's well - being and the future of their family. Saeko, on the other hand, could be both excited and a bit scared, as she has to balance her usual strong - willed self with the physical and emotional changes of pregnancy.
Some dedicated anime fanfiction communities could also be a good place to look. These communities often have users sharing their own works. You can join forums related to the anime that these characters are from and ask around for Takashi x Rei x Saeko fanfiction.
Perhaps the fanfiction could be set during a time when the group is split up, and Takashi and Saeko are on their own. They have to rely on each other completely. They could encounter a new type of zombie or a hidden danger that forces them to work together even more closely, and their feelings for each other start to turn into love.
Survival is a common theme. Given their apocalyptic setting, stories often show them relying on each other to stay alive. For example, they might fight zombies together while also strengthening their bond.
You can try Archive of Our Own (AO3). It has a large collection of fanfictions, and you may find some for Takashi x Saeko there. Just use the search function and type in the relevant tags.