Muddy Waters
Fred MacDowell
Jessie Mae Hemphill,(link to a video from that Deep Blues film of Mz Jessie doing "You Can Talk about Me")
R.L. Burnside
Slick Ballinger,
Chester "Howlin' Wolf" Burnett
Blind Mississippi Morris (Morris doing Wolf's "Smokestack Lightnin'")
And of course Tweed ;~)