Pentagram, Candlemass, Witchfinder General, Satan, Tygers Of Pan Tang, Judas Priest, Black Sabbath, Manilla Road, later Sentenced, Atlantean Kodex, Anvil Chorus, Cloven Hoof, Blitzkrieg, Helstar, Sanctuary....to name a few...
Granted, some have falsettos, but I still consider that clean.
"Information is not knowledge. Knowledge is not wisdom. Wisdom is not truth. Truth is not beauty. Beauty is not love. Love is not music. Music is THE BEST."