Mage Slayer (PHB '24)

General Feat (Prerequisite: Strength or Dexterity score of 13+)

You have practiced techniques useful in battling magic-users. You gain the following benefits:

Ability Score Increase. Increase your Strength or Dexterity score by 1, to a maximum of 20.

Counter Magic. Creatures who take the Magic action within 5 feet of you provoke Opportunity Attacks.

Concentration Breaker. When you damage a creature that is concentrating, it has Disadvantage on the saving throw it makes to maintain concentration.

Guarded Mind. If you fail an Intelligence, Wisdom, or a Charisma saving throw, you can cause yourself to succeed instead. Once you use this benefit, you can’t use it again until you finish a Short or Long rest.