Bands And Albums.

Sir Lord Baltimore - Ah yes, a person after my own heart. Title song Kingdom Come is very Black Sabbath-ish. Reportedly they were first band called "Heavy Metal" in Creem magazine.
Gamalon is great music, I have 4 of their CDs, I'd like to think they're not that obscure.
Here's some that I have/had the albums from:
Ultimate Spinach, Chocolate Watch Band, Mae Blitz, Tucky Buzzard, Hour Glass (Allman Bros band), Orpheus, Crazy World of Arthur Brown (not really too obscure - Carl Palmer start), Bloodrock, Porcupine Tree, Michael Stanley Band, Poundhound, Spooky Tooth (again not really too obscure).
I got plenty more if anyone wants to really dig into R&R musical history.

Hey Kick Asner -
There was also a band named Widowmaker with Dee Snyder - I know you're spot on with your description (especially calling out Luther Grosvenor - cheers to you for that), but interesting there were two Widowmaker bands.

Lothar was the group's theramin. In the early 70's Kim King came and auditioned for the band I was in in New Jersey. They had relocated from out west somewhere and minor success as an opening act for some groups.

The Dear Hunter. They have made what I can only call a concept album on crack, because it is not just one album, but SIX albums (the sixth has yet to be released). Here's a YouTube video with the first 5 albums in order: https://www.youtube.com/watch?v=J5eGNWtS-WM

Angel , very rarely known
https://www.youtube.com/watch?v=Q12rhJWE954

Vampy Snotwad and the Sickfucks (Psycho and Pig)

There album "Were Not Gay, We're f**k Queers" rocks

i can name four obscure bands...

Planet Jazz
Mere Mortals Bluegrass Band
THE 121's
The Spincasters

i can name four obscure bands...

Planet Jazz
Mere Mortals Bluegrass Band
THE 121's
The Spincasters

Ever thought of making all four into one big supergroup? Maybe for one big gig? Markapalooza

Short answer... No.

Longer answer....

But Kenny (gtr) and Mike (drums) play w THE 121's and The Spincasters.

Kenny will be helping PJAZZ out when he sits in on a cpl of dates that Bill (bassman) will be missing. I'll move over to bass and we'll be in trio mode w him playing the heads and doing most of the soloing.. He's a great rock, blues, and ctry gtrst but really is not a jazz cat by any stretch so it'll be interesting.

I've tried to get Sarah (fiddler/gtrst/bassist/vclst in MM's ) out to sit in w THE 121's at the trkstop but so far no dice.

Here is a band I had a lot of fun with:

https://www.youtube.com/watch?v=qRRihfwIQq0

Talbot