Luke Cage, Power Man.
Seriously.
Given muscle tissue like, say, a tiger’s, a 10 ton strength isn’t unreasonable.
Genetic treatments to give Human skin a Kevlar-like quality could be done (eventually).
In other words, The Punisher.
What about The Rocketeer? Sort of the same vein as Iron Man but waaay more plausible. Maybe not in the 1930s or the 80s but plausible today.
OK, you can have a rocket backpack. This is an actual thing. And you can fly around for a few minutes, or 30 seconds for the H2O2 versions. This makes you a superhero how?
What about The Green Hornet? I’m not overly familiar with the canon, but he seems like a bruiser with the powers of advantageous newspaper coverage, a kung fu chauffeur and a weaponised car.