Another possibility is a fanfiction set in an alternate universe where Raven and Damian are already married and they've been trying to have a baby for a while. When Raven finally gets pregnant, it's a time of great joy. They could go through all the typical pregnancy experiences like shopping for baby clothes, choosing a name, and decorating the nursery.
One possible plot idea could be the two of them dealing with the initial shock of the pregnancy. They might struggle with how to tell their families and friends. Another could be them preparing for the baby, like setting up a nursery in the Batcave or Raven's mystical realm. They could also face challenges from villains who see the unborn child as a potential threat or a tool for their evil plans.
You can try Archive of Our Own (AO3). It has a large collection of fanfiction, and you're likely to find many Damian and Raven pregnant fanfics there. Just use the search function and type in relevant keywords like 'Damian and Raven pregnant'.
There are several out there. Some focus on the medical side of Raven's pregnancy in a world where they have access to both normal and supernatural medical help. In one fanfiction, Damian is overly protective, which causes some tension between them as Raven still wants to be independent. It's a great exploration of their characters. Another fanfic shows how their families react to the pregnancy. Damian's family has their own set of expectations, while Raven's side has different concerns. These elements make for an engaging read.
A plot twist could be that the pregnancy is not what it seems. Maybe it's an illusion created by a villain to distract them from a bigger threat. Raven and Damian might initially believe it's real and start making all these plans, only to find out later that they've been tricked.
Their relationship would likely become more intimate. With a baby on the way, they would have to rely on each other more, sharing fears and hopes. There would be a deeper level of trust.
Well, perhaps there's a plot where Raven is injured during a battle. Damian, who has always been stoic, is overcome with worry for her. He stays by her side as she recovers, and during this time, they have deep conversations about their lives, fears, and hopes. This emotional connection builds up to a kiss. Or it could be a story where they are forced to pretend to be a couple for a mission. At first, it's all just an act, but as they play their parts, they start to feel real emotions and end up sharing a kiss.
Well, in such a fanfiction, it could be that an unexpected event led to Raven's pregnancy. Nightwing would likely be very protective. They might face challenges from their enemies who see this as a vulnerability. The story could also delve into their emotions, like Raven's fears and Nightwing's excitement about becoming a father, while still maintaining their heroic personas.
One great 'Damian and Raven Fanfiction' is 'The Bond Beyond'. It beautifully explores their relationship as they face a common enemy together. The author does an excellent job of depicting their personalities, with Damian's stoicism and Raven's inner turmoil coming through vividly.
A third idea is to focus on the relationship between Aquaman and his partner. How does his partner support him during this time? Do they have to adjust their relationship dynamics? It could also involve the partner taking on more of the traditional 'protector' role while Aquaman is pregnant.
A different fanfiction idea could be that Catwoman is pregnant and she teams up with other female villains who are also mothers or expecting. They form a sort of 'villain moms' group where they support each other, share their experiences, and even plot some less dangerous schemes together while taking care of their pregnancies.