Honestly, I think fans of classic dark fantasy might find 'Coraline' a bit too slender. It's more of a focused, eerie parable than a sprawling epic. The Other Mother's world has this chilling, domestic horror that gets under your skin differently than, say, a gothic castle full of monsters. It's the buttons-for-eyes thing – so simple, so viscerally wrong. That image has stuck with me longer than a lot of more complex dark fantasy lore. The pacing is tight, almost claustrophobic, which I appreciate, but if you're coming in expecting intricate world-building or a huge cast, you might be disappointed.
It's absolutely worth the few hours it takes to read, though. Gaiman nails that feeling of a child's loneliness being exploited by something predatory, which is its own kind of dark fantasy. The cat is a perfect character. I've re-read it a couple times, and it holds up because the fear is so psychological. It doesn't rely on gore; it relies on you imagining those cold, needle fingers. I lent my copy to a friend who loves grimdark, and she said it creeped her out in a way those books usually don't.