Another theme is growth. Fanfictions often show how both characters grow as individuals and as a pair. Tamaki might become more confident with Mirio's influence, and Mirio could also learn important lessons about himself through his relationship with Tamaki. It's all about their mutual development.
One place to find such fanfiction could be Archive of Our Own (AO3). Just search for 'amajiki tamaki x togata mirio' on the site and you'll likely get a good number of results. There are various genres and themes within these fanfictions, from friendship - centric ones to those exploring deeper emotional bonds between them.
The themes often revolve around his insecurities. Tamaki is a character full of self - doubt, so many fanfictions deal with him facing his insecurities head - on. Some fanfictions also have a theme of mentorship, where an older or more experienced character helps Tamaki navigate through his problems. There are also fanfictions that focus on his hero - like qualities that might be hidden beneath his shy exterior, highlighting his potential to be a great hero.
One common theme is his growth and development. Writers often explore how he overcomes his shyness and insecurities. Another theme is his relationships, like his friendships within the hero class or potential romantic relationships. Also, his experiences as a hero - in - training and how he copes with the pressures of that role are often explored in fanfics.
Some fanfics focus on the theme of support. In a 'male x mirio' relationship, they support each other through difficult times, whether it's dealing with personal problems or challenges in their hero - related tasks. It shows a really positive and heartwarming side of the relationship. And of course, there are also fanfics that play with the theme of the power dynamics between the two characters, which can lead to some unique and exciting plotlines.
A common theme is their bond. Since they are friends in the original story, fanfics often explore how deep that bond can be. It could be a story about loyalty, where they are always there for each other no matter what.