Vaultbreaker

Every heist needs "The Muscle", and you've trained your physique to fit this role perfectly. Someone to bear the heavy loads and break whatever stands in their way. 

"The Muscle"

3rd-level Vaultbreaker feature
When you choose this archetype at 3rd level, your trained physique has become an asset in more ways than one.

Big Muscles. You gain proficiency in the Athletics skill if you don't already have it. Your proficiency bonus is doubled for any ability check you make that uses this proficiency.

Break In. Whenever you make a check to disarm traps or open locks, you gain a bonus equal to your Strength modifier.

Pack a Punch. Choose one type of simple or martial melee weapon that lacks the special property. You gain proficiency in the weapon if you don't already have it. You may use your Sneak Attack against a target when using weapons of the chosen type as well as your unarmed strikes.
    Additionally, you may use your Sneak Attack when damaging objects that aren't being worn or carried and structures. You don't need advantage to use your Sneak Attack in this way if the attack uses your Strength modifier and you don't have disadvantage on the attack roll. All the other rules of Sneak Attack still apply to you.

Saving Throws. Some of the features in this subclass require a saving throw to resist the effects. The saving throw DC is calculated as follows:

Muscle Save DC = 8 + your proficiency bonus + your Strength modifier

Break Through

3rd-level Vaultbreaker feature
There may come a time when a lock can't be broken. In those cases, you're prepared to barrel through walls to get where you need to go.

If you take the Dash action on your turn and move at least 20 feet in a straight line, you may make one melee weapon attack or unarmed strike against a structure or object (that isn't being worn or carried) as part of the same Action or Bonus Action you used to Dash. This attack can benefit from your Sneak Attack even if you have already used it this turn.

Starting at 7th level, you aren't affected by difficult terrain caused by rubble and debris.

Smash 'n Grab

9th-level Vaultbreaker feature
You've quickened your reflexes to lock down a target at a moments notice. Whenever you use your Sneak Attack against a creature, you may use your reaction to attempt to grapple the target if they're within your melee reach.
    Additionally, you can make unarmed strikes with limbs that are grappling creatures. When you hit with an unarmed strike, you may choose one creature you're grappling that is your size or smaller. That creature must make a Strength or Dexterity saving throw (their choice) against your Muscle save DC. On a failed save the grappled creature and the target of the attack each take half of the damage dealt by your unarmed strike. On a success the target of the attack takes the the damage dealt by your unarmed strike and the grappled creature takes no damage and is no longer grappled.

Demolishing Charge

13-level Vaultbreaker feature
Few barriers can stand in your way when you get going. When you take the attack granted by your Break Through feature, so long as you continue to move in a straight line, you may apply the same to hit and damage roll to any structure or object (that isn't being worn or carried) directly in your path.
    During this movement you can move through a space occupied by creatures your size or smaller. When you do so they must make a Strength saving throw against your Muscle save DC. On a failed save, they take bludgeoning damage equal to your Strength modifier and are knocked prone. On a successful save, they take no damage and are moved 5 feet in a direction outside of your path.

Hit the Sweet Spot

17th-level Vaultbreaker feature
You've perfected how to use your nigh-unparalleled might when striking. Your melee weapon attacks, thrown weapon attacks, and unarmed strikes score a critical hit on a roll of 19-20.