The most popular Proto-Metal songs on Spotify • Featuring Steppenwolf, Jimi Hendrix, Iron Butterfly, Humble Pie, Vanilla Fudge, Mountain, Cactus, Hawkwind, MC5, Blue Cheer, Zebra, Spooky Tooth, Leaf Hound, Dust, Captain Beyond, Frijid Pink, Bloodrock, Sir Lord Baltimore & ASH • By volt.fm