Dean could get some new ideas about how to deal with the challenges they face. The fanfiction might offer creative solutions to their problems. He might also start to notice little details about Castiel that he hadn't paid much attention to before, like the way he looks at him or the things he says, which could change their relationship dynamic in a positive way.
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.
Dean would become more protective. His tough - guy exterior would soften as he takes care of the baby. He'd be more cautious in his hunts, not wanting to leave the baby unprotected.
I've read a fanfic where Dean's half - human nature led to some really interesting plot twists. In this story, he had to learn to control new powers that came with his changed state. It was exciting to see how the author incorporated the Supernatural lore into this new concept of Dean. It's called 'Half - Human Dean: New Abilities'.
Their relationship would likely become more complex. John would probably feel a stronger sense of protectiveness towards Dean. He might also feel guilty for not being able to prevent whatever caused the mpreg. Dean, on the other hand, might become more dependent on John in some ways, which is a big change from their usual dynamic.
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.
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.
One great 'female dean destiel' fanfic could be 'The Dean's New Perspective'. It offers a unique take on the characters where Dean is reimagined in a female role and the Destiel relationship unfolds in an interesting way. Another might be 'Female Dean in the Supernatural World' which delves deep into how a female Dean would interact with Castiel and the challenges she'd face in the Supernatural universe.
There's also the theme of toys coming to life in a way related to the Supernatural elements of the show. Maybe a toy becomes possessed and Dean and Castiel have to deal with it together, which could lead to some interesting character development and relationship building between them.
You can start by looking on Archive of Our Own (AO3). It has a vast collection of Supernatural fanfiction, including many great Sabriel and Destiel ones. Just use the search function and type in the relevant tags.
The combination of the Supernatural universe, which is already full of mystery and the supernatural, with the concept of dimension traveling makes for really exciting and unique storylines. And Destiel, the relationship between Dean and Castiel, adds an emotional depth and a fan - favorite ship aspect to it.