One possible plot could be that Danny and Sam face challenges in raising their baby while also dealing with Danny's ghost - fighting duties. Maybe the baby inherits some of Danny's powers and they have to figure out how to help the baby control them.
One possible plot could be that their daughter inherits Danny's ghost powers. She might struggle to control them at first, just like Danny did. Sam and Danny would be there to guide her, teaching her about the importance of using her powers for good. There could be a new villain in town who targets their daughter because of her unique half - ghost nature. And she has to learn to use her powers and the knowledge passed down from her parents to defeat the villain.
Well, perhaps in the future, Danny and Sam get married. They have a family and are trying to live a normal life, but their past as ghost hunters keeps coming back. Their kids start to show signs of having special powers or an interest in the supernatural. Sam and Danny then have to teach them about the world of ghosts while also protecting their family from old enemies that resurface.
The plot could involve some sort of mystery related to the pregnancy. Like, there could be a ghostly force that is either helping or hindering the pregnancy. And they have to figure out what it is and how to deal with it. Also, their friends like Tucker could play important roles in supporting them.
Vlad could be a great antagonist. He might see the baby versions of Danny and Sam as an opportunity to finally get rid of Danny for good. He could try to use their weakened state to his advantage and steal Danny's powers once and for all.
A plot could be that a magical spell gone wrong makes Sam and Danny age down to babies. Tucker discovers that there's a time limit to reverse the spell. Meanwhile, the two babies are exploring the world in a very different way, seeing things from a new perspective. This could lead to some heartwarming and funny interactions with their families and friends as they all try to solve the mystery of the spell.
One possible plot could be that all the ghosts in the Danny Phantom world decide to be on their best behavior for the wedding. They might offer unique gifts, like a ghostly flower arrangement that never wilts. Danny and Sam would have to deal with the normal wedding jitters, but also the added stress of keeping the peace between the living and the dead guests.
In this fanfiction, it could start with Danny Phantom turning evil due to an experiment gone wrong. As for Sam, she has always had a special relationship with plants. The evil Danny might start to use plants as his minions, controlling them to do his bidding. Sam, seeing this, decides to take matters into her own hands. She begins to study ancient plant lore to find a way to break Danny's control over the plants. Along the way, she might face many challenges, like Danny sending his plant - minions to attack her. But she doesn't give up, as she is determined to save Danny from his evil state and restore the balance between the supernatural and the natural world.
One possible plot could be that Danny and Sam decide to spend Christmas helping the ghosts who are usually left out during the holiday. They could use Danny's powers to bring some holiday cheer to the Ghost Zone. For example, they might organize a little Christmas party with ectoplasm - made decorations and treats that ghosts can enjoy.
Well, perhaps in the fanfiction, Danny and Sam have been through a lot together, like countless battles with powerful ghosts. One day, Danny decides it's time to propose to Sam in a very special way. He takes her to their favorite haunt (pun intended), a place where they first discovered a powerful ghost artifact. There, he gets down on one knee and asks her to marry him. And of course, she says yes.
One possible plot could be that Danny has finally defeated all the major ghosts threatening Amity Park. With the town at peace, he realizes his true feelings for Sam. They start planning a simple wedding. However, some of Danny's ghost enemies, not fully defeated, try to disrupt the wedding to get revenge on Danny. But with the help of their friends Tucker and Danny's family, they manage to fend off the attacks and have a beautiful wedding in the park, surrounded by their loved ones.