There are certain artists that I can understand their underground status due to the extremity of their nature like Grand Belial's Key or Jig-Ai, but there also exists a massive list of bands with an accessible sound and true authenticity that I will simply never understand their lack of recognition.
Examples:
Deceased
Melechesh
Frightmare
Nekromantheon
Repugnant
Oblomov
Examples:
Deceased
Melechesh
Frightmare
Nekromantheon
Repugnant
Oblomov