One possible plot could be Phoebe discovers she's pregnant and tries to keep it a secret from the magical community at first because she fears for the baby's safety. But as her pregnancy progresses, strange things start to happen, and she realizes she needs the help of her sisters.
Obviously, Phoebe's daughter would be a main character. She would likely have her own personality, powers, and goals. Phoebe herself would probably also be a major character, perhaps as a mentor or a source of conflict depending on the story.
There could be a fanfiction where Phoebe's pregnancy is a result of a magical spell gone wrong. In this story, she has to find a way to reverse the spell without harming the baby. It might involve her sisters helping her search for ancient spells and artifacts. Also, a great fanfiction could explore Phoebe's relationship with Cole during her pregnancy, if they were still in contact, and how that dynamic changes.
Phoebe and Cole's love story in 'Charmed' was a complex and passionate one. They met and were initially attracted to each other. Cole was half - demon, but Phoebe saw the good in him. Their relationship had many ups and downs. At first, they were deeply in love, getting married even. But Cole's demon side often caused problems, leading to many conflicts with Phoebe and her sisters. Eventually, their relationship couldn't withstand all the challenges, but it was a very memorable and intense love story in the series.
One popular Piper pregnant fanfiction might be found on FanFiction.net. You could search for stories that focus on Piper's pregnancy and how it affects her powers and relationships within the Charmed universe. Another place to look is Archive of Our Own (AO3). There are often many creative takes on this scenario in the Charmed fandom there.
If Piper hurts Chris, it would surely create a rift in the family dynamics. The Halliwell sisters would be caught in the middle, having to deal with Piper's actions and also help Chris. It could also lead to a change in Piper's character arc, as she'd have to come to terms with what she's done.
Yes, there are likely some out there. You can start by looking on fanfiction websites. Some might focus on how Phoebe's pregnancy affects her powers in the 'Charmed' universe. For example, it could explore if her premonition power becomes stronger or more erratic due to the hormonal changes during pregnancy.
One great charmed phoebe daughter fanfic could be about her daughter inheriting unique magical powers and having to navigate the magical world just like Phoebe did. Maybe she discovers a new spell that Phoebe never knew about and uses it to solve a big mystery in the magical community.
You can start by looking on fanfiction websites such as Archive of Our Own (AO3). It has a large collection of 'Charmed' fanfictions, and you can use the search function to specifically look for ones related to Phoebe being pregnant. Another option is FanFiction.net, which also has a wide range of 'Charmed' - related stories.
Common themes in 'Charmed Piper Chris fanfic' include growth. Chris is growing up and Piper is also evolving as a character. Fanfics might show how they help each other grow. Forgiveness is also a theme. Maybe Chris makes a mistake in the past or future and Piper has to forgive him. Or vice versa. And then there's the theme of legacy. Piper has a certain legacy as a Charmed One, and Chris is part of that legacy too. Fanfics can explore how they uphold or change that legacy through their actions.