Brawler

Increase your Strength or Constitution by 1, to a maximum of 20.
You have advantage on attack rolls against a creature you are grappling.
You are proficient with improvised weapons.
Your unarmed strike uses a d6 for damage. If you have natural weapons, the dice becomes a d8.
When you hit a creature with an unarmed strike or an improvised weapon on your turn, you can use a bonus action to attempt to grapple the target.
When you make an opportunity attack within 5 ft., you may attempt a grapple instead of making an attack.