Morgana is very common. He's always by the protagonist's side in the game, so he often plays an important role in fanfics too. Ryuji is also frequently seen. His energetic and sometimes reckless nature provides an interesting contrast to the female protagonist. And Ann, with her beauty and kind heart, is often included as a good friend or ally.
One of the most common is Yusuke. His artistic and somewhat eccentric personality makes for great interactions with the female protagonist in fanfics. Makoto is another. As the student council president, she brings a sense of order and intelligence to the story. And then there's Futaba. Her hacking skills and her journey of coming out of her shell are often incorporated into the fanfic when she's a supporting character.
Well, first off, Akechi is quite common. His complex character and his relationship with the Phantom Thieves add depth to the fanfic. Then, Haru is often in these fanfics. Her sweet nature and her own story arc related to her family's business make her an interesting addition. Also, the Velvet Room attendants like Igor or Lavenza might appear, guiding the female protagonist on her journey in a mysterious way.
The other Phantom Thieves are very common. Characters like Ryuji, who is brash and energetic, often appears alongside the female Joker. Morgana, the cat - like guide, is also frequently in fanfictions with her. And Ann, with her model - like looks and strong will, is another common supporting character.
Yosuke is often paired with the female protagonist. Their dynamic, which can range from friendly banter to a deeper connection, makes for interesting fanfic scenarios.
Family members can also be important supporting characters. Their parents or siblings might be in the fanfic, either giving advice on their relationship or causing some family - related drama. For instance, if Harry's family has concerns about him dating Camila, or vice versa.
One common supporting character could be their mutual friends in the music industry. For instance, Ed Sheeran might be a character who tries to mediate between them when they have a fight or misunderstanding. He could offer advice based on his own experiences with relationships.
Naruto himself is a very common supporting character. Since he has a connection with the Kyuubi, he often plays a role in the fanfiction. Sakura is also common. She might interact with the female Kyuubi, perhaps initially being afraid but then learning to understand her. Kakashi could be another one. His wisdom and experience can come in handy when dealing with the powerful and sometimes unpredictable female Kyuubi.
Junpei is another character that fans like to focus on. His comical yet loyal nature can be developed more in the fanfic. In new game plus, he could have new character arcs, like becoming stronger or more strategic in battles, and his relationships with other characters can be deepened in interesting ways.
Jaime is often a key supporting character. Given their complex relationship, his reactions and actions in relation to Cersei's pregnancy can be a major part of the story. Tyrion could also be important. His sharp mind and his own tenuous relationship with Cersei might lead to some interesting interactions during her pregnancy. And then there are the servants in the court, like Maester Pycelle who might play a role in taking care of Cersei during her pregnancy.
Sakura is often very popular. In many fanfictions, she is given more complex storylines. For example, some might explore her growth as a medical ninja further. Hinata is also a favorite. Her shy but strong - willed nature is often elaborated on, like in fanfictions where she has to step up and lead in Naruto's absence. Then there's Tsunade, a powerful female figure. Fanfictions may focus on her past and how she overcame various challenges to become the Hokage.
In 'Persona 3 Portable Female Fanfiction', Fuuka is an interesting character. Her shyness and her important role as the navigator in the game can be developed further in fanfictions. For example, she might overcome her shyness in more extreme situations. Elizabeth is also quite fascinating. Her mysterious nature and her knowledge of the Velvet Room can be the basis for some really exciting fanfiction plots. And don't forget about Koromaru's female - human form in some fanfictions, which can bring a whole new perspective to the story.
The protagonist is often quite popular in fanfiction. Writers can shape his story in many ways, explore his thoughts and feelings more deeply. Another popular character is Aigis. Her unique nature as a robot and her relationship with the other characters provide a lot of material for fanfiction writers.