That depends on how we're defining mature. If we're talking about sophisticated themes rather than just gore or nudity, some standout titles go well beyond broomsticks and black cats.
Monstress by Marjorie Liu and Sana Takeda is probably the crown jewel for a reason. The worldbuilding is an intricate blend of art deco aesthetics, Lovecraftian horror, and Asian-inspired mythology. The protagonist, Maika Halfwolf, isn't a 'witch' in the traditional sense but an arcanic, connected to a terrifyingly powerful entity. The story deals with trauma, the aftermath of war, and systemic oppression—it's dense, gorgeous, and genuinely unsettling in parts. The art is so unbelievably detailed you could spend an hour on a single page.
Then there's The Wicked + The Divine, which frames divine reincarnations as pop stars; Lucifer is a recurring figure, but many characters like Morrigan or Baphomet fit a very modern, performative witchy archetype. It’s a sharp satire on fame, fandom, and mortality. For something quieter, Blue is the Warmest Color uses magical realism subtly; the witch-like character Emma acts more as a catalyst for the protagonist's self-discovery within a raw, emotional romance. It's less about spells and more about the haunting quality of first love and artistic inspiration.
A recent discovery for me was 'The Night Eaters' by Marjorie Liu again, with art by Takeda. It’s a horror story about a Chinese-American family where the mom is a terrifyingly powerful entity making her kids clean up a haunted house. It’s funny, deeply creepy, and explores generational trauma and cultural expectations through a supernatural lens. Maturity here comes from the complex family dynamics, not just the body horror, though there's plenty of that too.
I’d skip anything that just uses witchcraft as a power set for a superhero plot unless that’s specifically what you want. These books use the witch archetype to explore much darker, weirder, and more psychologically fertile ground.