Brawler

Brawlers are fighters that, unlike most others, rely on their body and what's around to fight, rather than using formal weapons. However, they are not monks; they don't channel Ki, nor have lived in cloistered monasteries.

Most Brawlers specialize in unarmed combat, but also know how to use whatever's around to fight. Sometimes it can be something as simple as smashing an enemy in the head with a rock, breaking a branch off of a tree to use as a club, smashing a bottle to use as an improvised dagger, or even beating an enemy over the head with the detached limbs of a creature.

Bareknuckle

You are proficient in unarmed combat and improvised weapons. Additionally, your damage die with unarmed strikes increases equally to the progression of unarmed damage in the Monk class. Also, the damage increases every fourth level, going up one die type.

Levels 1-4: 1d4
Levels 5-8: 1d6
Levels 9-12: 1d8
Levels 13-16: 1d10
Levels 17-20: 1d12

Calloused

You have unarmed defense equal to 8 + your Constitution modifier.

Stone Cold Brutality

When you score a critical hit with an unarmed or improvised weapon attack, you deal the maximum damage on the die.

Thesz Press

When you take an attack action on your turn, you can instead make your first attack with your action a grapple. If you succeed at grappling your opponent, they also fall prone.

Ground & Pound

You always hit enemies who are prone, grappled, incapacitated, paralyzed, petrified, restrained, stunned, or unconscious, and have advantage on the damage roll.