One great 'Barney Stinson and Robin Scherbatsky fanfic' is 'The Reunion'. It beautifully captures their complex relationship post - breakup. It shows how they still have that spark between them and how they navigate through their feelings while also dealing with their friends' reactions.
One possible fanfiction could be that Barney and Robin find out they're pregnant unexpectedly. Maybe they initially panic as they had not planned it so soon. But then they start to get excited about becoming parents and think about how to combine their different lifestyles. Barney might start thinking of how to be a cool dad, while Robin pictures herself as a strong, working mother.
One common theme is redemption. Barney, for example, has a complex character and in fanfiction, his journey towards becoming a better person for Robin is often explored.
A good fanfic about them should stay true to their characters. Barney is known for his elaborate schemes and Robin for her tough exterior but soft heart. If the fanfic can capture these traits while also exploring their relationship in new ways, it's great.
A prevalent theme can be the anticipation of the baby's arrival. Writers might focus on the couple decorating the nursery, choosing baby names, or going to doctor appointments. There could also be a theme of the couple learning about parenting, like reading books or taking classes. Sometimes, the fanfiction might even incorporate elements of the show's humor into these pregnancy - related situations, making it both heartwarming and funny.
Their love story started casually. They were friends first and gradually feelings developed over time through shared experiences and spending a lot of time together.
Well, it depends on the author's imagination. Some might show them struggling to adjust, while others could paint a picture of seamless adaptation and newfound happiness with the baby.