Neonchameleon
Legend
Beowulf of course is (a) mundane and (b) can hold his breath for an hour. He's mundane but not bound by the mechanics of the real world. He's exactly what's wanted as a fighter.Batman
King Arthur
Ulysses from the Odyssey
Green Arrow
Beowulf
Edit. Krillin
Arthur, not sure. If I don't think he ever faces anything more dangerous than a CR5 hill giant that's not a magical human.
Batman, Green Arrow, and Odysseus all behave as rogues when dealing with big things. And this is one of my huge issues here - I see much more role for mundane rogue/gadgeteer slipping round the edges and being a wild card than I do for mundane fighter trying to parry a storm giant's blow without being turned into a tent peg or strawberry jam.