So I don’t know much about mainstream heroes, but I know a lot about The Venture Bros and One Punch Man. Literally nobody in TVB, unless I’m allowed to say that like Hunter mobilizing the entirety of the Office of Secret Intelligence. OPM has a few. Saitama obviously. He’s immune to the law of cause and effect. He can punch holes in reality and spacetime. Tatsumaki can scoop up entire cities and crush the monster goop out of them. She can stop bombs and use them herself. She could smash a military base together and hurl the explosive result at another base. She couldn’t be stopped in our world. Metal Knight has an army of machines that might be able to stand up. He probably doesn’t have the pure numbers, but he has us on technology handily. I think the real question is can he stop our immense firepower and artillery from overwhelming his robot army. I’m not totally up to date, but I haven’t seen enough of Blast to give it to him with confidence. I want to say Blast could on roughly Saitama logic: his punches rend space and time. There was a period where Garou could have, but he arguably wasn’t a hero at the time. That’s probably it for OPM.