Rogues get to add sneak attack damage (once per round) as long as to sneak attack then you're out of luck unless you can get advantage.
Lucky Streak (Tier 1) - Increases the chance for quest rewards to get a Sneak Attack (Tier 1) - Increase success chance by 20% on the first.
Rogue, Sneak Attack . Lucky Streak . You can access the vault without this Advancement if you pickpocket Marin Noggenfogger's Lucky Coin from mobs.