Yes, I am sure there were many underground Metal bands out there that only existed a short period of time until disbanding for good. Some of them released maybe a demo or two, and some even managed to put out a record or two...
Let's have this threat exclusively for them because I am sure many of us may know some Metal bands that kind of never got the respect and/or attention that they would have deserved when they still existed.
Here's a Canadian Death Metal band (w/ some Industrial elements) INNER THOUGHT that (unfortunately) ceased to exist around in 1996-1997 (I guess). The band was a solo project of Bobby Sadzak (ex-LETHAL PRESENCE, ex-STRAPPADO, ex-SLAUGHTER) with variable line-ups and many guests musicians.
Coolest band to come out of Bucharest, Romania. That one album they have done is excellent. Great sounding, catchy, solid badass true metal. I happened to see them live and they were phenomenal, and super cool when I met them.
Best band bar none coming out of that part of the world.
Out of local Finnish bands, I like a few that had one good album:
Downfall were a mix of power and goth, sort of. Hooky. Rocked hard anyway. That song was a minor underground hit.
I really like those nasty, female vocals. Cool song.
Neither are active anymore. I don't think if Downfall ever made a second album, but I know Ironica did, but I never picked that one up.