By 'combat jobs', do you mean 'things that can be used as excuses for adventures'? The usual would be 'working for a noble' or equivalent, with the players having a set patron whose political machinations require all kinds of vaguely nefarious activities to be done, probably in places where the law doesn't look too closely. Then the noble turns out to be a Yugoloth, drama ensues, etc, etc.
Also: gladiator arenas are a thing that you get in fantasy cities. Waterdeep has one, complete with Clerics who promptly heal/resurrect any fallen, to keep things acceptable for a NG-aligned city. More evil cities certain have them. It's another useful 'combat release valve' that the players can tap whenever they're desperate to get away from social heavy stuff and use their class features.
Also: gladiator arenas are a thing that you get in fantasy cities.
On a less drastic note, though, professional athletes. Boxers and wrestlers could have levels in barbarian or monk.I agree, gladiator combats are a Neutral Evil or Lawful Evil thing. Turning murder into a spectator sport is about as evil as humans can possibly get.
I agree, gladiator combats are a Neutral Evil or Lawful Evil thing. Turning murder into a spectator sport is about as evil as humans can possibly get.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.