Celebrated artist Gerhard Richter offers unique pieces for sale, his Atlas collection. These boards include the newspaper clippings, photos and sketches which are the source material for much of his work. Here's one Atlas board and one of his photographs inspired by it.
The interesting thing about this artist to me, is his diversity. "His early work is of blurred figurative paintings, both with and without colour followed by seductive abstract paintings, with a colour palette that is either brilliant or subdued. His surprisingly diverse range of work has received prolonged discussion from critics, especially due to Richter's disregard for 'traditional' stylistic progression and his use of photographs." See more examples of his work below.