CiG
Room with a View
I think Lucifer's Friend's Ride the Sky might be a more complete heavy metal song than anything on the first two Sabbath albums tbh.
It's a shame the rest of that album doesn't hold up as well as that song does.
Other massively influential bands for me are Uriah Heep and Steppenwolf.
Are you trying to argue with me about songs that are widely considered to be where speed metal originated from?