Truth is that there is no safe or harmless way to physically stop someone, besides using some grappling to pin them and then restrain them with handcuffs or something.
Superpowers like Spiderman's web or telepathy are a cute way of doing it, but it's hard to make a whole cast of superpowered people like that. If you think about it, the only two students with "sure" ways of restraining someone are the tape guy and Momo (if she has time and information). Kaminari could make someone pass out somewhat safely if he had fine control over his electricity, but...
Superpowers like Spiderman's web or telepathy are a cute way of doing it, but it's hard to make a whole cast of superpowered people like that. If you think about it, the only two students with "sure" ways of restraining someone are the tape guy and Momo (if she has time and information). Kaminari could make someone pass out somewhat safely if he had fine control over his electricity, but...