There are a vast number of fanfics out there, and while the 'Danny x Sam' pairing is common in certain fandoms, it might be a bit difficult to find one with the 'Danny is tortured' aspect. You could also try reaching out to fan communities dedicated to the relevant series or characters. They might be able to point you in the right direction.
One common theme is the idea of redemption. Derek might be seen as a character who has a past to make up for, and Stiles helps him in that journey. Another is the theme of trust. They have to learn to trust each other despite their differences. And love, of course, is a major theme as their relationship develops.
One great 'Stiles x Derek Mates' fanfic is 'The Bond Between Us'. It beautifully explores their relationship development. The story delves into how they come to terms with being mates and face various challenges together in the supernatural world of Beacon Hills. It has some really touching moments where their connection is palpable.
You can find Derek x Stiles x Scott fanfic on websites like Archive of Our Own (AO3). It has a vast collection of fanfics in different genres and ratings. Another place is FanFiction.net, which also has a good number of such fanfics. Just search for the relevant tags like 'Derek x Stiles x Scott' or related keywords like 'Teen Wolf poly relationship' and you should be able to find a lot of stories.
One popular Derek x Stiles x Scott fanfic is 'The Pack's Bond'. It focuses on their unique relationships within the pack. It shows how their individual personalities interact and create a strong bond among them. There are also fanfics like 'Three's a Company' which delves into their more emotional connections, exploring love and friendship in a supernatural setting. Another great one is 'Pack Unity' that has a lot of action scenes intertwined with their developing relationships.
Derek could be initially hesitant. He has his own past traumas and might worry about how he could be a part of the child's life. However, as he sees Stiles struggling to handle it all alone, his feelings for Stiles would push him to become more involved. He would start to see the son as a new beginning, a chance to build a family in a way he never thought possible before. He'd offer his werewolf skills to keep the child safe and teach him about the supernatural world if needed.
The theme of self - discovery also runs through these fanfics. Stiles, in particular, may go through a process of self - discovery as he experiences the physical and emotional changes that come with mpreg. He has to learn to adapt and understand himself in a whole new light, which in turn affects his relationship with Derek.
The unique world - building of the omegaverse. In these fanfics, the alpha - omega dynamics add a new layer of complexity to the relationship between Stiles and Derek. It's not just a regular love story, but one that involves biological and social hierarchies.
Yes, there are quite a few. You can try searching on some fanfic websites like Archive of Our Own. There you might find various stories about Danny and Dora's adventures together, or some unique interpretations of their relationship, which could be either platonic or more of a friendship - based, creative exploration.