One popular theme is the characters from Kim Possible getting quirks and attending UA. It's interesting to see how they would fit into the My Hero Academia world with their new powers.
Fanfiction.net is also a great place. There are likely to be some crossovers or fanfictions related to both Kim Possible and My Hero Academia. Browse through the relevant categories and you might find some interesting reads.
The deaf hero might be highly observant. Since they can't rely fully on sound, they would have to be really good at noticing visual cues. For example, they could be very perceptive of body language, which could be useful in battles or social interactions.
One possible plotline could be about the next generation of heroes. Maybe the children of the current heroes are starting their own hero journey at UA High. They might face new villains with even more complex quirks.
A different idea is that some of the students from U.A. High School go on a field trip to Bikini Bottom. There, they learn about the different 'quirks' the underwater creatures have, like Sandy's ability to live underwater as a squirrel. And at the same time, they have to help SpongeBob and his friends with a problem, like stopping a giant sea monster that the normal underwater heroes can't handle. This would involve a lot of teamwork between the two groups.
One possible plotline could be that Naruto mistakes a character from My Hero Academia as a threat to the ninja world. So, he banishes them to prevent any potential harm. For example, if he sees a powerful quirk user like All Might in the wrong context, he might think they are a new kind of enemy.
The complex relationships he has. For example, his relationship with his family. Fanfiction writers can explore different scenarios and emotions related to it, making for good fanfiction.
Overusing his quirk is a common reason. Deku often pushes himself to the limit with One For All, and it can take a toll on his body. So in fanfiction, this could be a simple yet effective way to have him pass out.
In a fanfiction that gives them new powers or abilities, most of class 1a would be intrigued. Sero might be immediately thinking of how to use those new powers in combat. However, if the new powers are too outlandish or don't fit their characters at all, there could be some pushback. Jiro might be critical and say that it doesn't make sense for her character to have such a random power that has no connection to her music - based quirk.
The theme of unrequited friendship could also be present. Maybe one character considers another as a close friend, but the other doesn't feel the same way. In the high - stakes world of 'My Hero Academia', with all the hero training and battles, these unbalanced relationships can add depth to the fanfiction. It shows that even in a world full of heroes, not all relationships are straightforward.