Midoriya would be a great character to pair Shinsou with. Midoriya's positive attitude and strong sense of justice could complement Shinsou's more reserved and sometimes cynical nature. They could learn a lot from each other, especially when it comes to using their quirks in different situations. Another good pairing could be Bakugo. Their contrasting personalities would create a lot of interesting dynamics. Bakugo's explosive nature and Shinsou's calm mind - control could lead to some intense and humorous interactions.
Deku would be a great character to pair with Obito. Deku's pure - hearted nature and his drive to be a hero could contrast with Obito's more complex and troubled past. Obito could see in Deku the kind of hero he once wanted to be, and he could help Deku in ways that All Might or other heroes couldn't, especially when it comes to dealing with darker aspects of the hero world.
A great plot idea could be Shinsou going undercover in a villain organization. Since his quirk is so useful for deception, he could infiltrate and gather intel. Or perhaps a story where Shinsou has to train a group of new students with difficult - to - control quirks. He'd have to use his own experiences and his mind - control quirk in a mentoring way. Also, a plot where Shinsou discovers a new aspect of his quirk during a life - or - death battle, which gives him an edge and changes the course of the fight.
Dabi could be a great character to pair with Tomura. They are both villains and their powers and personalities could create some interesting interactions. Maybe they could team up for a particularly difficult mission or have a power struggle within the League of Villains.
A very interesting character to pair Mirio with is Luffy from One Piece in a crossover. Luffy's carefree and determined nature along with his stretching powers would be an interesting contrast to Mirio's Permeation. They could form an unlikely but strong alliance. Another character is Ichigo from Bleach. Mirio and Ichigo could fight side - side against Hollows and other threats, with Ichigo's sword skills and Mirio's hero abilities complementing each other. Also, pairing Mirio with Naruto would be great. Naruto's never - give - up attitude and his use of ninjutsu could create a unique dynamic when combined with Mirio's hero powers.
One good character to pair with Kendo Itsuka could be Tetsutetsu. Since they are from the same class and have similar physical - based quirks, there could be a lot of interesting interactions between them. They could train together and support each other in battles.
Akko and Deku would be an interesting pair. Akko is full of enthusiasm and determination in her pursuit of magic, much like Deku with his journey to become a great hero. They could inspire each other and learn from their different approaches to achieving their goals.
Midoriya could be a great character to pair with Tsuyu. They both have a strong sense of justice and are very determined in their hero training. They could support each other in battles and share their experiences about growing as heroes.
Definitely Deku and the Red Ranger. Deku's determination and growth as a hero in MHA would pair well with the leadership qualities often associated with the Red Ranger. They could learn from each other's ways of fighting and inspire their respective teams.
You can start by looking on Archive of Our Own (AO3). It has a large collection of 'boku no hero academia' fanfictions, and there are many dedicated to Shinsou. Just use the search bar and type in relevant keywords like 'Shinsou' and 'boku no hero academia'.
Another interesting pair could be Black Widow and Tsuyu Asui. Black Widow is a master spy and assassin, and Tsuyu has her unique Quirk and a very down - to - earth personality. Black Widow could teach Tsuyu some self - defense and espionage skills, and Tsuyu could show Black Widow the importance of teamwork and loyalty within the U.A. High group.