Witchfinder Conclave

Adapted from this homebrew.

Employed mostly by Taranthia, the Witchfinders are a group of Rangers who excel at sniffing out practitioners of Magic and Black Magic.

Spell Seeker

Starting at 3rd level, your senses have been highly trained to identify magic use. Whenever a spell is cast within 30ft of you, you are aware of it, even if the casting had no visible effect or components. You do not know the identity of the caster, only that casting took place.

Spell Breaker

Also starting at 3rd level, you act swiftly in response to magic use. Whenever you can see someone casting a spell within 30ft of you, you can use your reaction to make a weapon attack against them. If you hit, the caster must make a concentration check against your Maneuver DC. If they fail this check, their casting is unsuccessful.

Warded Hunter

You have met a witch or two in your time, and know their ways. At 7th level, you have advantage on saving throws against magical effects.

Forbidden Mark

At 11th level, you learn a unique maneuver only available to Witchfinders, making use of your enemies' tools to bring them to justice. Successfully hitting with this maneuver also marks your target. When you mark a target in this way, you always know the location of this creature, and are aware any time it casts a spell, regardless of distance. This mark lasts until the creature dies, or you remove it using an action, or it is removed with a Remove Curse or Greater Restoration spell. The maneuver is as follows:

Witchfinder's Strike

When you target an enemy spellcaster with a weapon attack, you may expend one Superiority Die to gain advantage on attacks against that creature for the rest of your turn. You may add the superiority die to the damage of your first successful attack this turn.
You cannot exchange this unique maneuver, and it does not count towards your total number of known maneuvers.

Spell Sealer

Starting at 15th level you learn to permanently damage a witch's ability to cast spells. Whenever a creature fails the concentration check as a result of your Spell Breaker feature, the spell slot is expended and they are unable to cast that spell again. This effect can only be removed by a Remove Curse or Greater Restoration spell.