Well, one unique feature is the combination of different universes. For example, when it crosses over with something like Doctor Who, you get time - traveling elements added to Destiel's story. Another is the new character interactions. When Destiel characters meet those from other shows or universes, it creates fresh and unexpected relationships.
A very interesting 'destiel crossover fanfiction' is 'Destiel in the Star Trek Universe'. It takes the essence of Destiel's relationship and places it in the futuristic and space - exploring world of Star Trek. The way the characters adapt to the new environment and interact with the Star Trek characters is really engaging.
Another interesting one is 'When Worlds Collide: Sterek and Destiel'. In this story, the two universes are somehow merged, and the characters have to adapt to this new reality. It delves deep into the relationships of both pairs, exploring how Derek and Stiles' dynamic is similar to or different from Dean and Castiel's, while also having a great overarching plot about saving both merged worlds from destruction.
You can start by looking on popular fanfic websites like Archive of Our Own (AO3). It has a large collection of fanfics, and you can simply use the search bar to type in 'sterek and destiel crossover' to get a list of relevant stories. Make sure to check the ratings and tags to find the ones that suit your taste.
One common theme is the exploration of forbidden love. Both Destiel (Dean and Castiel) and Sabriel (Sam and Gabriel) relationships often go against some sort of 'rules' in the Supernatural world. Another theme is sacrifice. Characters are often willing to sacrifice a great deal for their loved ones in these fanfictions.
I really like the Sabriel fanfic 'Gabriel's Return'. It has a great story line that involves Gabriel coming back to Sam in a very unexpected way. Regarding Destiel, 'Heavenly Bonds' is a great choice. It goes into detail about the spiritual connection between Dean and Castiel, and how it impacts their actions and decisions in the Supernatural world.
In fanfiction, 'destiel wing kink' often adds an extra layer of fantasy and uniqueness to the relationship between Dean and Castiel. The idea of wings can symbolize power, protection, and vulnerability. For some fans, it's a way to explore the deeper, more ethereal aspects of their relationship, something that goes beyond the normal physical interactions shown in the original series.
Well, it could mean that Dean is exploring different interpretations of his relationship with Castiel. Maybe he's curious about how fans see their dynamic.
There's also 'The Road to Us'. It's a bit of a longer read but well worth it. It delves deep into their relationship, exploring their past traumas and how they overcome them together. The story has a great balance between action and the development of Destiel's relationship, making it a very engaging read.
One common theme is the exploration of their relationship. The pregnancy often serves as a catalyst to deepen the bond between Dean and Castiel. It forces them to communicate more openly and face their feelings for each other.