Jo Ann Kelly (1944 - 1990) was an English blues singer. Had she followed the urging of industry people and come to the US, her career could have been on the magnitude of Janis Joplin. Instead, she remained close to the English blues scene. She was humble, genuine, and massively talented.
My heroes in popular (as opposed to classical) music are few. They must have deep-rooted soul and/or striking originality. Also some eccentricity. Robert Johnson, Bob Dylan, Bob Marley, Björk. Now I add another name to the list.