Forgotten heavy bands from late 60's to early 70's


Have been a fan of hard rock/metal since high school. Always liked the heavy/physcadelic bands equally to the metal bands I grew up with Ozzy-Maiden and Scorpions ect. Recently on Youtube I discovered some heavy/physcadelic bands I was unaware of. 13th Floor Elevators-Five Day Rain-Probe Direction-The Hook and Vahalla. Are these bands albums worth persuing? Feel free to mention any other band that deserves to be heard. Look forward to your responses.
dayglow
Not a Heavy Metal band but a Heavy Classic Rock band, Spooky Tooth made a classic album, "Spooky Two", great album. That's the only one I can recommend. They put out others you might want to explore if you like Spooky Two.
I always thought Witchfinder General was pretty cool. They sounded a lot like Sabbath
-Stongly second the 1st Sir Lord Baltimore.
-1st Trettioariga Kriget (genius brain melting stuff)
-John McLaughlin - Devotion
-Patto 1st
-High Tide - Sea Shanties
-Budgie - 1st or Squawk
-Steamhammer - Speech, (also check out Armageddon)
-Captain Beyond
-Skid Row (w/ Gary Moore)
-Guru Guru - UFO
-Groundhogs - Split
-Pink Fairies - Never Neverland
-Deviants 3
-Ursa Major - Ursa Major (Dick Wagner before R&R Animal)
Fortunately there are lots of others... have fun hunting em' down!