One good character to pair with Kendo Itsuka could be Tetsutetsu. Since they are from the same class and have similar physical - based quirks, there could be a lot of interesting interactions between them. They could train together and support each other in battles.
It could also be interesting to pair Itsuka Kendo with Shoto Todoroki. Shoto's complex past and his cold exterior could be softened by Itsuka's warm and friendly personality. They could help each other grow as heroes and individuals, with Itsuka perhaps helping Shoto open up more and Shoto inspiring Itsuka to reach new heights in her abilities.
One plot idea could be Kendo Itsuka going on a special training mission in a mysterious location. Along the way, she discovers new powers within herself and has to overcome various challenges. Another idea is a story where she teams up with an unlikely ally to solve a mystery in the hero world.
A plot could revolve around Itsuka Kendo forming an unexpected alliance with a villain. Maybe she realizes that the villain has some redeeming qualities or is being forced into their actions. This would put her in a moral dilemma as she tries to figure out how to handle the situation while still being a hero.
There are several fanfiction platforms where you might find such stories. Archive of Our Own (AO3) is a great place to start. You can search for 'My Hero Academia Kendo pregnant' and it'll likely bring up relevant fanfics. Just be sure to check the tags and ratings to ensure it's the kind of story you're looking for.
A more romantic storyline could also be interesting. Picture Izuku realizing his feelings for Itsuka during a school event. He might be shy at first, but his friends could encourage him to pursue her. Meanwhile, Itsuka might be oblivious at first, but as Izuku starts to show his true feelings, she begins to see him in a new light.
For Izuku, start with his existing traits like his tenacity and self - sacrifice. In the fanfiction, he could learn from Itsuka's confidence in her own abilities. For example, he might see how she doesn't doubt herself as much as he does, and that could lead to him becoming more self - assured.
Their relationship could start as mutual respect for each other's skills. Midoriya would admire Kendo's leadership and combat abilities, while Kendo would be impressed by Midoriya's determination. As they spend more time together, they might become friends. They could start training together and sharing tips on how to be better heroes. This would strengthen their bond.
One plot idea could be how Kendo manages her hero duties while being pregnant. Maybe she has to face challenges like hiding her pregnancy from villains who might target her or her unborn child. Another could be the support she gets from her classmates or fellow heroes, like how they step in to help her when she can't do certain tasks due to her pregnancy.