One common theme is family. Since the female lead becomes the male lead's adopted daughter, there is a focus on building a new family dynamic. It could be about learning to trust and love within this new family structure.
One popular 'I became the male lead's adopted daughter' novel is 'The Adopted Daughter of the Male Lead'. It has an interesting plot where the female lead, after becoming the adopted daughter, changes the fate of the male lead and those around them in a fantasy world.
Perhaps the story involves the female lead using her new position as the male lead's adopted daughter to change the fate of the family or the world around them. She could have some knowledge from her previous life (if it's that type of story) and tries to prevent disasters or improve the family's standing in society. Like, she might know about a business deal that will go wrong and uses her influence as the daughter to stop it.
The female lead's character development might start with her being in a vulnerable state when she first becomes the adopted daughter. As she adapts to her new life, she becomes more confident. For example, if she was initially shy, living with the male lead and being part of a new family gives her opportunities to grow and speak up for herself.
I recommend "The National Fairy" to you. The female protagonist of this book is the daughter picked up by the male protagonist. She is a divine beast that has slept for a thousand years. After she was awakened, she entered the modern society of the 21st century and tried her best to adapt and become an outstanding modern woman. Other than that, there was also a plot where the scheming male protagonist was reborn for revenge, and the female protagonist had explosive martial strength. I hope you like my recommendation. Muah ~
The name of this novel might be " Lord Snow Eagle ". This was an online novel with the theme of adventure and combat. It told the story of a young man's growth. After experiencing various dangers and challenges, he became a powerful lord. The male protagonist was initially adopted by the female protagonist's uncle, but the two gradually developed feelings for each other.
I recommend the novel "Little Delicate Lady of the Reborn Marquis's Mansion" to you. It tells the story of the female protagonist, who was the legitimate daughter of the Grand Tutor's Mansion. Her family was killed, her husband betrayed her, and the secret of her adopted son made her suffer even more. After her rebirth, she returned to her youth and started her life anew. This novel had elements of a fight in the palace. The male protagonist was an adopted son, and he was one of the few nobles in the family. Where would the female protagonist go this time? I hope you like this fairy's recommendation. Muah ~😗
Many comics have plots where the female lead is the male lead's adopted daughter. Here are some possible names:
1 " My Master ": This is a Japanese manga about a young man who accidentally became the adopted daughter of his master and gradually established a deep relationship with his master.
Pokémon: This is a very famous Japanese anime in which the female lead Pikachu is the adopted daughter of the male lead, Jenny Turtle.
3." Tokyo Ghoul ": This was a Japanese manga and animation that told the story of a human becoming a ghoul after death. The female lead, Kimki Ken, was the adopted daughter of the male lead, Hyuga.
4 " Melody of the Mermaid ": This is a Japanese manga and animation that tells the story of the female protagonist, Shimazu Nai, who is the adopted daughter of the male protagonist.
5 " Vampire Hunter D ": This is a Japanese manga and animation about the male protagonist, Dae-in, who is the adopted daughter of the female protagonist, Vampire Hunter D. The two of them grow up together and fight against the vampires.
The plot may revolve around the challenges the female lead faces as the stepmother. For instance, she might face opposition or suspicion from the people around the male lead. She could be trying to bring positive changes to the family while also dealing with her own feelings towards the male lead. There could be a backstory about how she got into this situation, perhaps a magical or accidental occurrence. And as the story progresses, she might have to navigate through social norms and expectations regarding her relationship with the male lead.
I'm glad to hear that you like modern romance novels! According to your needs, I recommend you a novel called "Cute Baby Little Assist: Daddy, Let Go of My Mommy." The plot was about the female lead, Ye Fan, who was a paparazzi who dug into other people's privacy. In the end, she was found to have a son. The male protagonist's surname is An, and the female protagonist is the adopted son of the male protagonist's family. It matches your setting. The plot was sweet and it was a relaxing and interesting modern romance novel. I hope you like this fairy's recommendation. Muah ~😗