Elitist (5e Feat)
From D&D Wiki
With all your practice in combat, you've learned how to use all of your senses in the heat of battle. As such, you know how to inflict the most amount of damage with the least amount of effort.
- As a bonus action, you can make a Wisdom (Insight) check contested by another creature's Charisma (Deception) check. If you win the contest, you score critical hits against the targeted creature on a roll of 19-20 for one hour.