1 Ian Gillan
Ian Gillan is an English singer and songwriter. He originally found success as the lead singer and lyricist for Deep Purple, and the original singer on the rock opera concept album Jesus Christ Superstar by Andrew Lloyd Webber, where Gillan had the leading role (Jesus Christ).
Severely underrated - 4 octave vocal range (same as Freddie and Rob Halford) and Gillan was the guy who put together the basic elements of metal singing style, including screams. There were screams before him but he made screaming part of the vocal art. - Metal_Treasure
He is one of the best rock singer ever...
2 Hansi Kürsch
Hansi Kürsch, born Hans Jürgen Kürsch, is the lead singer, lyricist, co-composer and bassist for German power metal band Blind Guardian . Heavily influenced by Freddie Mercury, he creates a huge choir effect by overdubbing his own voice multiple times in complex, overlapping vocal harmonies. He records ...read more.
Most underrated, together with Michael Kiske - Metal_Treasure
I'd say he's more unnoticed than underrated. - IronSabbathPriest
3 Randy Blythe
David Randall "Randy" Blythe is the vocalist and lyricist of American heavy metal band Lamb of God and side-project band Halo of Locusts.
4 Chuck Billy
Charles "Chuck" Billy is an American vocalist, who is best known as the vocalist for the thrash metal band Testament.
James Hetfield is good, but to me, Chuck Billy is the best thrash metal vocalist. - CostcoHotDogs
5 Michael Kiske
Michael Kiske is a singer best known as the former lead vocalist for the German power metal band Helloween.
Michael Kiske and Hansi Kürsch are the best singers on this list and should be more appreciated.
The gap between their vocal talent and level of popularity is the widest, meaning they are most underrated. - Metal_Treasure
6 Tom Araya
Tomás Enrique "Tom" Araya Díaz is a Chilean American musician, best known as the bassist and vocalist of the American thrash metal band Slayer.
Underrated? Are you kidding me? He's the opposite.
He is OVERRATED.
Does he have influential Thrash Metal vocals? Maybe.
Does he have good Thrash Metal vocals? No!
Get him off this list.
7 Blaze Bayley
8 Paul Dianno
9 Tim 'Ripper' Owens
Timothy S. "Ripper" Owens is an American heavy metal singer who first gained attention as the lead singer of Judas Priest, and then Iced Earth. He took the nickname "Ripper" from the Judas Priest song "The Ripper" during his time in the tribute band "British Steel". He currently performs with Beyond ...read more.
10 Jon Oliva
John Nicholas Oliva, known as Jon Oliva, is an American composer, multi-instrumentalist and singer. Co-founder of the metal band Savatage and the rock opera Trans-Siberian Orchestra. He's got a real 4 octave range, able to morph the sound of his voice to any style, from John Lennon and Freddie Mercury, ...read more.
11 Jarkko Ahola
Jarkko Kalevi Ahola is a Finnish performing artist, composer and singer, best known as a metal singer. He is the vocalist, bass player and one of the three songwriters of the metal band Teräsbetoni. He also started a solo career as Ahola, a metal band.
You should check out his new band AHOLA where he sings in English. This guy really deserves more fame. An amazing voice.
He's really a great singer who deserves more attention. One of the reasons for being unnoticed is that he sings mostly in Finnish.
Songs: Teräsbetoni - Teräksen Taakka, Missä Miehet Ratsastaa, Paha Sanoo.
Those who are interested can visit my list Top 10 Teräsbetoni Songs. - Metal_Treasure
12 Eric Adams
Eric Adams has been the singer of the American heavy metal band Manowar since its inception in 1980. Previously, he sang for a group called LOOKS, a band which also included future Manowar bassist and childhood friend, Joey DeMaio.
He's really underrated. Manowar may not be a super super amazing band but Eric is a very good singer. Not perfect but very good. He performed the longest sustain/scream in metal (by far) - 33 seconds in the song Thor. - Metal_Treasure
13 Howard Jones
Howard Jones (Born July 20th, 1970) is an American Heavy Metal vocalist. He currently fronts the band Light the Torch (Formerly Devil You Know), but is best known for his tenure in the band Killswitch Engage from 2002 to 2012 and was a vocalist for the now defunct Blood Had Been Shed.
14 Ian Fraser Kilmister
15 Tobias Sammet
Tobias Sammet is a German metal musician, best known as the vocalist and primary songwriter of the power metal band Edguy, as well as the founder, main singer and bassist of the metal opera Avantasia.
16 Sebastian Bach
Sebastian Philip Bierk, known professionally as Sebastian Bach, is a Canadian heavy metal singer who achieved mainstream success as frontman of Skid Row from 1987-96. Since his departure from Skid Row, he has had many television roles, acted in Broadway plays, and leads a solo career.
Most of the guys here aren't even underrated. Some are overrated, but I never seen bach on greatest lists. Just listen to the song Wasted Time and feel his scream
17 Ronnie James Dio
Ronnie James Dio (born Ronald James Padavona; July 10, 1942 – May 16, 2010) was an American heavy metal singer, songwriter and musician. He fronted and/or founded numerous groups including Elf, Rainbow, Black Sabbath, Dio and Heaven & Hell. He is credited with popularizing the "metal horns" hand gesture ...read more.
Not That Underrated But Still, Great - BeatlesFan1964
18 Robb Flynn
He's a very good singer with a range from B♭1-E♭5 - christangrant
19 John Bush
John Bush is a singer who was first in the band Armored Saint however he then went on to join Anthrax after they got Joey Belladonna their last singer out of the band. John Bush then left Anthrax in 2005 though briefly rejoined in 2009 only to leave again in 2010
20 Tony Martin