Honestly, I spent ages searching for something that captures that specific Raven Cycle energy—the mix of modern-day magic, found family, and that aching, beautiful prose. A book that truly got there for me was 'The Atlas Six' by Olivie Blake. It's got that academic, secret-society vibe and deeply complicated, brilliant characters orbiting each other, though it's definitely more 'dark academia' and leans heavier on the philosophical bickering. The magic system is intricate and intellectual.
If you're more into the rural, ley-line magic and the sense of a place being a character, I'd suggest 'The Near Witch' by Victoria Schwab (her earlier stuff). It's a standalone with a haunting, atmospheric quality. It doesn't have the sprawling ensemble, but the mood is pitch-perfect for that 'something old sleeping under the hills' feeling that Stiefvater nails.
For the friend-group-on-a-quest dynamic with witty banter, Samantha Shannon's 'Priory of the Orange Tree' has elements of that, though it's epic fantasy. The real trick is finding that balance of mundane and magical; 'V.E. Schwab's 'Gallant' might scratch the 'lonely protagonist discovering a hidden, gothic world' itch, which was a huge part of Blue's journey.