In what sense of the word, 'hero?' There are many. And any or all of them may appeal to any one player at a particular moment. No guarantees they'll be what you expect them to be at the time you expect them to be it.
Ya can't even guarantee they'll be the protagonists (that sense of the word hero.) That would be bad GMing if it happened. But it does happen.
How's about some recent examples from campaigns I'm involved in. (tune out now unless you really want to read about my games. There's nothing new, just illustrations of the above statement.)
My Dwarves campaign: the PCs are national heroes. They've earned the title. Done many things to benefit the Dwarven Kingdom. They are patriotic, fervant, willing to commit mass genocide. They think themselves heroes.
My (brand new) Champions game: we have a character who conducts bizarre and painful experiments on people. A thief who likes to cut people. An alien/human hybrid that has disdain for all humanity. A total nut case who occasionally snaps and casually commits murder. A big hulking brute who likes to smash things and has set up a smuggling operation. Now none of the PLAYERS think these guys are heroes. But the mad scientist thinks he is hero of science. The alien hybrid thinks he is better than mere humans, doesn't matter what he does to them, they're just ants. The slashy thief is far too cynical to think he's a hero, but he thinks he's likeable. The psycho tries to be a decent person but there's that casually killing thing (and a raft of other psychosis.) And the big brute/smuggler happens to be a used car salesman, so we know he's evil. But they'll all step up to battle threats to their country, because that's what they're paid for.
The Age of Worms game I'm playing in. My character is morally inflexible, pushy and prone to violence. She says it's all part of being warrior caste and thus part of personal dharma. She considers herself to be very much a hero.
Ya know I've even heard of games where the PCs are likeable, friendly, helpful, think first and don't engage in wholesale slaughter at the drop of a hat. May see one one day.