Saw Winwood open two years ago for Clapton, great show all around. I don’t remember his vocals blowing me away but he is pretty old now. What era are you referring to? I’ve seen some great vocalists like Daltrey, but past their prime. I’ve seen some amazing shows but not that many vocalists that stand out. Here’s a small list though.
Susan Tedeschi (soulful, powerful, smooth)
Bono-80s versión (Range, power)
Sting
David Lee Roth (More of a showman but during original VH years, Dave could hold his own)
Adam Lavine
Daltrey, past prime but still good
Adam Duritz in 90s