Robert Plant, singer with Led Zeppelin, heavy metal rock and roll; right?
Well, not quite because they began as a folk/rock group and were originally called The New Yardbirds. "Bron Yr Aur" or "Battle of Evermore" or "Going to California" are a long way from heavyweight rock and roll.
As a solo artist Plant has never lost contact with his folk roots or with other genres of music which he has explored over the years and what follows is a small selection and it is notable that his voice is still as good as it was all those years ago, it might even be better.
For me his best work came from his collaboration with Alison Krauss and the album called "Raising Sand" The last video here is a very tongue in cheek blugrass version of Black Dog. The quality is maybe not so good and why American audiences insist on squealing like stuck pigs is a mystery to me and probably everyone else. But if you can ignore that it really is worth while.