Path of the Abolisher
Some barbarians walk the path of frenzy and rage to the fullest, while some others follow tribal totems, but You are different. You follow your hatred of magic. You might be driven by revenge to slay a magic user, or you follow the old traditions and believe that all magic is evil and corrupting... Your will is like iron, and your muscles are steel. Your sheer mental strength is enough to shrug of most spells.
Starting at 3rd level you become more resilient against magical attacks. On saving throws against spells and other magical effects you have an advantage while raging.
Breaking the Shackles
Starting at 6th level, your mind becomes infused with your hatred towards magic, making it almost impossible to affect you with spells. Whenever you fail a saving throw against a mind affecting spell or magical ability, you can choose to enter rage as a reaction. While raging, you can make another save against the effect every turn.
Also at 6th level, your weapons strike with such force and brutality they overcomme resistances as if they were magical. Unfortunatelly, you believe magic items are inherently evil, and you would never use one.
Senses of the Destroyer
Beginning at 10th level, you become so attuned to seeking out magic, you gain a special sense. With this sense, you can detect magical items, or powerful magic users. Also, you can roll perception to determine whether a spell has been cast in the area recently. A spell usually leaves a "mark" on the enviroment for equal hours to its level, though this may vary on the discretion of the Dungeon Master
Starting at 14th level, your attacks against spellcasters become obliterating. While raging, you roll all attack rolls against spell casters and magic users with advantage. Also, you critically strike against such foes with a roll of 19 or 20.