Here's some (on the more obscure side) heavy LP's I'd recommend you to check out for starters...from memory so hopefully correct...
Blue Cheer - Outside Inside (1968)
Bloodrock - same (1971)
Lucifers Friend - same (1970)
Pulse - same (1968)
Highway Robbery - same (1972)
Demian - same (1972)
Bolder Damn - Mourning (1971)
Night Sun - Mournin (1972)
Sir Lord Baltimore - Kingdom Come and same (1971-72)
...and if you dig this - also check Masters Of Reality - same (1988 i think)...
Blue Cheer - Outside Inside (1968)
Bloodrock - same (1971)
Lucifers Friend - same (1970)
Pulse - same (1968)
Highway Robbery - same (1972)
Demian - same (1972)
Bolder Damn - Mourning (1971)
Night Sun - Mournin (1972)
Sir Lord Baltimore - Kingdom Come and same (1971-72)
...and if you dig this - also check Masters Of Reality - same (1988 i think)...