A popular 'Beckett Disappears' fanfic is 'Finding Beckett: A Race Against Time'. This fanfic is interesting because it not only deals with the search for Beckett but also delves into the relationships between the other characters as they are forced to work together. It has a great plot that unfolds gradually.
One great 'Beckett Disappears' fanfic could be 'The Search for Beckett' which focuses on the characters' journey to find Beckett after his disappearance. It has really engaging dialogue.
It could be a very interesting plot. Maybe Beckett disappears because she wants to protect her unborn child from some unknown danger. Or perhaps there are some secrets related to her pregnancy that force her to go into hiding.
One great fanfic could be one that focuses on the emotional depth between Castle and Beckett during that episode. It might explore their unspoken feelings in more detail, adding more internal monologues for both characters.
One possible reason is that she is in danger. There could be someone or something that wants to harm her or her unborn child, so she has to disappear to stay safe.
Another place to check is FanFiction.net. There are many users who post their own stories there, including those related to 'Beckett Disappears'. Just use the search function to look for it.
I'm not sure specifically which Beckett pregnant fanfics are popular. You could try searching on fanfic platforms like Archive of Our Own. They have a large collection of fanfics and you can filter by the relevant tags such as 'Beckett' and 'pregnant' to find some interesting ones.
I'm not sure specifically about popular Beckett tortured fanfics as it depends on the fandom. There are so many different fanfic communities out there. However, in a well - known fandom, if Beckett is a popular character, there could be some that gain a following. It would require searching through relevant fanfic platforms to find out.
One interesting plot could be that Beckett discovers she's pregnant right before a big, dangerous case. She has to decide whether to tell Castle immediately or wait until the case is over. Another plot might be that the pregnancy has some sort of strange medical mystery attached to it, which ties into Castle's love for mystery - solving. Maybe the doctors are stumped by some unusual symptoms and Castle uses his writer's imagination to help figure it out.
One common theme could be the idea of rescue. Since there's a baby involved in being kidnapped, often the character Beckett might be on a mission to rescue the baby. Another theme could be the struggle against the kidnappers, showing Beckett's determination and courage in the face of danger.
One highly recommended 'Castle trying to find Beckett' fanfic is 'The Search for Her' on AO3. It has a great plot that really delves into Castle's emotions as he tries to find Beckett. Another good one is 'Finding Beckett: A Castle's Journey' on Fanfiction.net. It's well - written and has some interesting twists. And then there's 'In Search of My Partner' which is a shorter but very engaging fanfic available on a smaller fanfic website.
I'm not sure of specific 'Beckett and Daughter kidnapped' fanfics off the top of my head. You could try searching on fanfic platforms like Archive of Our Own. They have a large collection of fan - created stories and you might be able to find something related by using relevant keywords in their search bar.