Ranger who specializes in tracking the arcane/hunts magic users.

Arcane Stalker Magic

Starting at 3rd level, you learn an additional spell when you reach certain levels in this class, as shown in the Arcane Stalker Spells table. The spell counts as a ranger spell for you, but it doesn’t count against the number of ranger spells you know.

Horizon Walker Spells

Magical Study

Your dedication to studying and tracking the arcane has made you familiar with the various styles of magic and other knowledge. As a result, whenever you make a Intelligence check, you gain a bonus to the check equal to your Wisdom modifier (minimum of +1). If you pass an INT check (arcana) to learn more about a spell cast in combat, you learn the spell's: name, duration, range, casting process requirements (V/S/M), and the level that the spell was cast at.

In addition, you gain proficiency in one of the following skills of your choice: Arcana, History, Nature.

Mage Bane

At 3rd level, you learn to enhance your strikes with the very energy you hunt.

As a bonus action, choose one creature you can see within 90 feet of you that has cast a spell this combat. The next time you hit that creature on this turn with a weapon attack, all damage dealt by the attack becomes force damage, and the creature takes an extra 1d8 force damage from the attack. When you reach 11th level in this class, the extra damage increases to 2d8.

Arcane Detainment

At 7th level, you learn to Shield your mind from magical assaults. As a bonus action, you can cast the [spell]Forbiddance[/spell] spell with this feature, without expending a spell slot.

The spell's damage is halved (rounding down)[2d10], the affected area is reduced to a 120ft square and the duration is reduced 10 minutes. Once you use this feature, you can’t use it again until you finish a long rest.

Suppressing Impact

At 11th level, you can arcanely seal off any sound in the immediate area of your target for a short moment in time. When you take the Attack action for the first time this turn, you can choose to have no sound be created within or pass through a 5-foot-radius sphere centered on a point you choose within range. Any creature or object entirely inside the sphere is immune to thunder damage, and creatures are deafened while entirely inside it. Casting a spell that includes a verbal component is impossible there. This affect lasts until the end of your next turn. 

If at least one other hostile creatures is within the Suppressing Strike, you can make one additional attack against a creature in the radius.
You may use this ability a number of times equal to your proficiency modifier and regain all uses on a long rest.

Arcane Retaliation

At 15th level, you gain the ability to counterattack when facing a magical foe. If you are forced to make a saving throw against a magical affect, you can use your reaction to make one weapon attack against the quarry. You make this attack immediately before making the saving throw. If your attack hits, your save automatically succeeds, in addition to the attack’s normal effects.

You also gain evasion.
Through training you also have gain the ability to better avoid magical and other area effects, such as a red dragon’s fiery breath or an ice storm spell. When you are subjected to an effect that allows you to make a Dexterity saving throw to take only half damage, you instead take no damage if you succeed on the saving throw, and only half damage if you fail.