It depends which witch hunter novel you mean, right? My mind went straight to 'The Last Apprentice' series (the Spook's books) – the protagonist is a kid named Tom Ward. He's the seventh son of a seventh son and gets apprenticed to the local Spook, who's basically the county's monster and witch hunter. Tom's journey is all about learning the trade while constantly wrestling with the morality of it, especially when he befriends a girl who might be a witch. It's a classic coming-of-age setup but with a lot of grim, earthy folklore.
If you're thinking of something grittier and more adult, maybe 'The Witcher' series? Geralt of Rivia is the obvious answer there. He's a mutated monster hunter for hire, but witches and sorceresses are a huge part of his world. Calling him just a 'witch hunter' feels a bit reductive, though. He’s more of a cynical philosopher with swords, constantly entangled in political schemes way above his pay grade. The books follow him as much as they follow Ciri, his surrogate daughter.
Then there are books like 'Witch Hunter' by K.S. Marsden, where the protagonist is literally named Hunter Astley, a modern witch hunter battling a rising darkness. It’s much more straightforward in its premise. So yeah, you gotta be more specific. The archetype is common, but the execution varies wildly from YA apprenticeship tales to dark fantasy epics.