List of bands (21):

Mammoth
Marianas Rest
Marije
Masquerage
Masterplan
Mastodon
Megadeth
Memphis May Fire
Metal Church
Metal Factory
Metalite
Metallica
Michael Schenker
Michael Schenker Group
Ministry
Miscreance
Misfire
Młot Na Czarownice
Monstrosity
Moonspell