German Oak - Niebelungenlied sounds like an early black metal album. The self-titled album is better, though. It was recorded in a WWII air bunker.
I could go on and on, but there are plenty online lists of great krautrock. Of the more popular groups, Amon Duul II and Ash Ra Tempel have aged particularly well.
edit: Can, Guru Guru and Silverbart all have blues influences, although Can is more influenced by Miles Davis' electric period.