Dave Grohl covered many bands, and played many alternate versions of his songs.
There are also a lot of side projects like Probot.

Probot (feat. Dave Grohl)

01. Centuries Of Sin (w/ Cronos / Venom)

02. Red War (w/ Max Cavalera / Soulfly, Sepultura)

03. Shake Your Blood (w/ Lemmy / Motörhead)

04. Access Babylon (w/ Mike Dean / C.O.C.)

05. Silent Spring (w/ Kurt Brecht / D.R.I.)

06. Ice Cold Man (w/ Lee Dorrian / Cathedral / Napalm Death)

07. The Emerald Law (w/ Wino / Place Of Skulls / The Obsessed)

08. Big Sky (w/ Tom G. Warrior / Celtic Frost)

09. Dictatorsaurus (w/ Snake / Voïvod)

10. My Tortured Soul (w/ Eric Wagner / Trouble)

11. Sweet Dreams (w/ King Diamond / Mercyful Fate)

12. I Am The Warlock (w/ Jack Black / Tenacious D)