Krautrock is the most boring James Brown B-side ever recorded being played sans guitar in slow motion by autistic robots
Within rock? The Beatles (actually experimented harmonically instead of just playing drones), Pink Floyd (easily as structurally inventive as Popol Vuh), ELP (appropriated elements of contemporary classical that wasn't shite - see their cover of Ginastera's Toccata, a world away from the po-faced Stockhausenisms of Krautrock), the Grateful Dead (continued to cultivate a distinctive yet almost anachronistic style of improvisational rock in a post-psychedelic musical environment, never falling victim to noise like Faust did), the Velvet Underground (were capable of mixing sonically experimental elements with pop songs, something Faust never managed until their IV), Queen (far greater feeling for structure/form than Faust, albeit quite trite musically).