One common theme is healing. Rei has been through a lot, so in many fanfics, the reader is there to help her heal emotionally. For example, the reader might be the one to encourage Rei to open up about her past traumas.
There's 'Rei's New Friend' which is also quite popular. In this fanfic, the reader enters Rei's world in an unexpected way. It shows how the reader's presence gradually changes Rei's life for the better. The writing style is very engaging, making you feel like you're really part of the story.
The main characters would obviously be Izuku Midoriya and Rei Todoroki. Izuku is the protagonist of the main series, a quirkless boy who dreams of becoming a hero. Rei is Shoto Todoroki's mother, who has her own complex backstory and powers. In a fanfiction, they would be the central focus, with their interactions and character development driving the story forward.
One possible plot could be that Izuku discovers Rei's hidden strength. Maybe Rei has some untapped quirk potential that Izuku, with his analytical mind, helps her realize. They could team up to face a new threat in the My Hero Academia world that requires both of their unique skills and experiences.
Some Naruto characters would likely be very confident in a Highschool of the Dead - Rei fanfiction setting. For example, Naruto himself would probably jump right into action against the zombies. He'd see it as another challenge to overcome and would use his Rasengan or other jutsus without hesitation. Sasuke, on the other hand, would be more calculating. He'd analyze the situation of the zombie apocalypse and the role of Rei and others before making a move.
Midoriya's friends like Uraraka and Iida would be extremely worried. They would immediately start looking for him. Uraraka might use her quirk to search in the air, while Iida would lead the ground search with his speed. Bakugo, on the other hand, would be furious. He would probably go on a solo mission to find Deku and take on Todoroki without hesitation.
Another interesting concept is a Todoroki family fanfic set in an alternate universe. In this universe, the family could be a normal, happy family from the start. There would be no hero - villain drama, and it could show their day - to - day life, like family dinners, outings, and how they deal with normal family issues.
Some Tumblr blogs are dedicated to sharing and recommending fanfics. You can search for tags like #Todoroki family fanfic on Tumblr. There might be some users who regularly post their favorite fanfics or even write their own short Todoroki family fanfic pieces on their blogs.
Well, Spy x Family fanfiction can be really interesting. Some fanfictions might explore different relationships between the characters in more depth. For example, they could focus on the bond between Anya and Loid in a new situation that wasn't shown in the original manga or anime. It's also fun to see how authors play with the spy and assassin themes in unique ways.
His friends would probably take care of him. Midoriya would be very eager to help, using his kind-hearted nature. He would make sure Todoroki is fed and comfortable.