One popular plot twist could be the protagonist using 'The Gamer' abilities in unexpected ways during a major battle in the My Hero Academia world. For example, they might use a gaming - like inventory system to pull out a super - rare item that gives them an edge against a powerful villain. Another could be the fusion of My Hero Academia's Quirk system with 'The Gamer' leveling system, where a character's Quirk gets upgraded in a way similar to leveling up in a game.
One common plot twist could be that the Gamer abilities interact with the My Hero Academia world in unexpected ways. For example, the character with Gamer powers might suddenly discover a new 'game level' that is actually a secret villain lair in the MHA universe. Another popular plot twist could be the origin of the Gamer powers being tied to some ancient MHA legend. Maybe it was a power passed down from a forgotten hero who was also a gamer in a sense.
A plot twist could be that the Quirk system and Stands are somehow related. Maybe there was an ancient event that split the power into two forms. This would open up a whole new exploration of the lore in both universes. Characters would have to reevaluate their understanding of their own powers and how they interact with those from the other universe.
One interesting plot twist could be the main character's gamer abilities suddenly evolving in an unexpected way. Maybe they gain a new power that completely changes the way they interact with the world of My Hero Academia. For example, instead of just having enhanced physical stats like in the game, they can now manipulate time briefly, which throws off all their enemies and allies alike.
A really interesting plot twist could be that the symbiote from the Spider - Man universe attaches itself to a major villain in My Hero Academia. This would make the villain even more powerful and unpredictable. The heroes would have to figure out how to deal with this new threat that has a combination of a quirk and the symbiote's abilities.
Katsuki Bakugo is also a common character. His explosive personality can be interestingly combined with the gamer concept. Maybe a gamer - like Bakugo who is always looking for the next 'level up' in terms of his quirk strength and hero status, constantly challenging others in a competitive, almost game - like way.
The combination of the 'gamer' concept with 'My Hero Academia' is appealing. It allows for a different take on the existing powers and abilities in the show. For example, characters can level up their quirks like in a game, which is a fresh idea.
A popular pairing is Izuku Midoriya and Harry Potter. They both are the main protagonists in their respective universes, so fans like to imagine them as friends or even comrades in a crossover. They share some similarities, like their strong sense of justice and their will to protect others. Midoriya's admiration for heroes could extend to Harry, and they could learn a great deal from each other's experiences.
One interesting plot twist could be when a character from My Hero Academia ends up being a key figure in the Fate Stay Night world's power struggle. Maybe a hero's quirk is actually related to the magic system in Fate Stay Night in a way that no one expected.
One popular trope is the 'Gamer Underdog'. The OC is underestimated because their gaming - related quirk seems silly at first, but they prove everyone wrong. Another is the 'Gaming Team - up'. The OC teams up with other heroes who also have quirks that can be useful in a game - like scenario, like a hero who can create mazes and they work together in a virtual - reality - based mission. There's also the 'Gamer Upgrade' trope, where the OC continuously levels up their quirk through gaming - like challenges within the hero world.
Another reason is that it appeals to a wide range of fans. Those who like the My Hero Academia universe get to see their favorite character in a new light, and gamers can relate to the game mechanics incorporated. It's a blend that can attract both the anime/manga fans and the gaming community, so it has a broader audience compared to regular fanfictions.