So what should I Fighter be able to do out of combat?
Allow me to introduce Elliot Spencer from the TnT show Leverage.
Elliot is, in the show's parlance, The Hitter, the group's muscle whose job it is to beat on problems the rest of the team can't hack, steal, or talk their way past.
It would be really easy for the writers to make him a dumb, useless brute only good in a fight like a D&D Fighter. But these are some of the best pulp writers in the game, so he's not.
Elliot has been a hitter all over the world and in dozens of conflicts of varying size and type.
He can identify weapons by their sound or the shape they hold under clothing.
He speaks almost as many languages as the team Grifter for the same reason.
He's been in so many fights that he has a great sense of when someone has hostile intent from body language and mannerisms.
He's been muscle for so many bad guys that he knows security layouts and standard patrol routes.
He also knows the base operations of those types of organizations.
He cooks.
He sings.
He's good at covert communication.
In five seasons, he lost three fights. And no one tried to balance his badassery by making him incompetent at the other ways he contributes to the team.
Also, he never just stands there like a lump and punches ceaselessly, but baby steps.