Progressive vocalists

[Yesspaz]

Jon Anderson - Yes

Phil Collins - Genesis (although I like the Gabriel-era music much better)

David Gilmour, Richard Wright (and less-so, Roger Waters) - Pink Floyd

Ty Tabor first, Doug Pinnick second - King's X

Geddy Lee - Rush (the later albums, when he lost the screech)

Mark Solomon - Stavesacre (great range, great versatility)

Steve Perry - Journey

Greg Lake - King Crimson

John Wetton - King Crimson and Asia

and perhaps the greatest vocalist ever, tonality and quality-wise, but not range-wise...
Derri Daughtery - The Choir



I'm sure there are others.

Yesspaz out.