I have always been fascinated with the watercolor artwork used in the closing credits of the Bonanza TV series. Even in re-runs, these watercolors are incredibly bright and full of richly colored images over underlying hand sketches.
From the little I've read, there were primarily two artists responsible for these which were not credited as individuals. In fact, their work was buried under the heading of the Art Department or some such.
Apparently, their names were never recorded, and no records exist which might aid in tracing their futures after Bonanza.
Outside of DVDs or VHS tapes, it's very difficult to find images of these watercolors online.