As one of the most formidable frontmen of classic rock, Robert Plant showcases his genre-hopping mastery both solo and with company. He formed The Honeydrippers to make vintage R&B (“Sea of Love”) and pairs up with Alison Krauss to craft bluegrass-tinged poetry (“Rich Woman”); he also reunites with fellow Led Zeppelin alum Jimmy Page for some high-energy rock ‘n' roll (“The Only One”).