Well, character crossovers are often a cool concept in 'boku o hero fanfic'. Imagine a hero from this universe meeting a hero from another well - known superhero universe. It can lead to really unique and exciting storylines. Also, exploring the villains in new ways, like giving them more complex backstories or motives that make them more than just the 'bad guys' is quite interesting.
Izuku Midoriya is often a very popular character in 'boku o hero fanfic'. His journey from being a quirkless boy to a powerful hero gives a lot of room for creative interpretations. Katsuki Bakugo is also popular. His complex personality and his relationship with Midoriya provide great material for fanfic writers.
The Boku no Hero manga is finished. It reached its conclusion after a successful run, leaving fans with a complete narrative and memories of an exciting journey.
Well, 'boku no hero novel' is probably about the adventures in the world of heroes. It could have new storylines that didn't make it into the main anime or manga. It may focus on a particular character's growth, like Midoriya's journey in a different light, or introduce new characters and their unique quirks within the hero - filled universe.
One popular idea could be creating an alternate origin story for a character. For example, giving Deku a different quirk acquisition experience that still leads to his growth as a hero.
It could be Midoriya. Imagine Midoriya getting access to Iron Man's technology. He's already a determined and intelligent hero - in - training, and with Iron Man's tech, he could become even more powerful. He might struggle at first to adapt to the new technology, but his strong will would drive him to master it and use it to protect others in new and exciting ways.