Lum could be a great addition. Her relationship with Ataru already has a lot of history, and her presence could create some interesting love triangle - like situations with Sakura. It would add a layer of drama and complexity to the story.
Another character could be Shinobu. Since she also has a past with Ataru, her reaction to Ataru's new relationship with Sakura could range from jealousy to acceptance. This could create more sub - plots and give more depth to the overall fanfiction.
Ten could also be included. As a friend of Ataru, he could provide some comic relief. He might accidentally get in the way of Ataru and Sakura's relationship, thinking he's helping Ataru but actually making things more difficult, which could lead to some humorous and also heart - warming moments.
The enchanted objects in the castle like Lumière and Cogsworth would be great. They add humor and charm to the story. Also, Gaston could be included in a different way, like he has a change of heart and tries to help them. And Belle's father could also be a key character, perhaps he discovers something important about the curse.
Naruto could be a great addition. His friendship with Sakura and his complex relationship with Kabuto in the original series could add an interesting dynamic. For example, Naruto might suspect something is going on between Sakura and Kabuto and try to interfere or understand what's happening.
Well, they could have a wise old mentor figure. This person could be an older neighbor who has lived through a lot and gives them valuable advice when they face difficulties in their relationship or in their adventures.
For a more villainous touch, including Voldemort or his followers could create high - stakes situations. Bellatrix Lestrange could be a terrifying adversary for Harry and Gabi. On the other hand, adding new original characters, like a powerful but reclusive wizard who lives in the Forbidden Forest, could also make the story more exciting.
Definitely Cristina Yang. She has such a strong personality and her interactions with Callie and Arizona could add a lot of spice to the fanfiction. Her no - nonsense attitude and brilliant surgical skills could create interesting storylines, like when she might compete with them in a surgical competition or give them some tough - love advice on their relationship.
Arya could be a great addition. She has her own set of skills and knowledge that could add depth to the story. Murtagh is also an interesting character. His complex relationship with Eragon and his own journey could bring in a lot of drama. Nasuada, with her leadership skills and strategic mind, could play a crucial role in any fanfiction scenario. For example, in a story where there is a war, Nasuada could be leading the troops while Eragon and Saphira are dealing with a magical threat.
Mario could be a great addition. Since Luigi is Mario's brother, his presence could add some family - related drama or comical moments. Sonic could also be included. As Tails' friend, Sonic's brash and confident personality would contrast well with Luigi's more timid nature.
Kyon could be a great addition. He often has an interesting perspective on Haruhi's antics and his interactions with both Haruhi and Mikuru could add depth to the story. Also, Yuki could be included. Her stoic nature contrasts with Haruhi's exuberance and Mikuru's more timid personality, creating some interesting dynamics.
Annabeth could be a great addition. She can provide her strategic mind and wisdom. For example, when Percy and Nico are on a quest, she could stay back at the camp but offer advice through Iris - messages. And when they get stuck, her knowledge of architecture and mythology can help them find solutions.
Natsu could be a great addition. He could be the fun - loving uncle figure who always gets the baby excited with his boisterous personality. His presence would add some humor to the story, like when he tries to teach the baby some of his fire - based magic tricks in a not - so - safe way, and Gajeel has to step in.