Anything from Progressive Rock artists who can play their instruments, create structurally interesting musics, with varying themes often blending with the lyrics, thus creating even concept albums as a whole, sound landscapes which are great for visualisation (most songs with vocals will do as well imagining their own stories) will do. I recommend: The Lamb Lies Down On Broadway by Genesis, IQ - Tales From The Lush Attic f.e.
As well as Jazz - Hard Bop, Post Bop, Fusion. Great exercise to focus on every part of individual instrument. It clearly shows how little aware we are and all we care about is just a simple melody to tap our feet to and not discovering style and passion of every individual band member.