Hip-hop and jazz might be genres most open to collaboration, yet rock n’ roll surely claims its fair share of artists and session rats addicted to cameos and guest appearances, side projects and super groups. After careful consideration and vetting, we’ve compiled a list of a half dozen of rock’s busiest (and most highly caffeinated) collaborators. We’re talking those inveterate workaholics like Josh Homme and Dan Auerbach, whose lives are a seemingly endless succession of studios, stages and video shoots. Would modern rock even exist without all their tireless creativity?

Josh Homme**  **

Homme is the Kevin Bacon of rock: every musician on the planet is no more than six degrees away from the 12-foot-tall stoner-rock god. In addition to Queens of the Stone Age, Kyuss and the star-studded Desert Sessions, he’s a charter member of Them Crooked Vultures, also featuring fellow collaboration fiend Dave Grohl, and Eagles of Death Metal, who just dropped their latest album, Zipper Down. These accomplishments represent just the tip of the iceberg, however. His various credits (Discogs lists nearly 400!) comprise a list as sprawling and tangled as Al Capone’s rap sheet. Ever wondered if a single musician has worked with Sir Elton, Mastodon and The Prodigy? Homme is your answer.

Dan Auerbach** **

When Auerbach isn’t churning out blues-rock with fellow Black Key Patrick Carney, or leading his new project The Arcs, he’s holed up in a vintage studio somewhere assisting other musicians create awesome music. The proud Ohio native is one of the most gifted producers and session whizzes of his generation and possesses an increasingly impressive track record to support it. The high-profile credits include Lana Del Rey’s crazy successful Ultraviolence, Ray LaMontagne’s Supernova and Valerie June’s folk gem Pushin’ Against the Stone. For my money, though, Dr. John’s Locked Down, released in 2012, is just as awesome. Contributing his skills as producer, guitarist and back-up singer, Auerbach helped the Doctor to make one of his eccentric joints something funky and moody like early-’70s classics In the Right Place and Dr. John’s Gumbo. Don’t sleep on it.


PJ Harvey**  **

Who wouldn’t want to collaborate with Harvey? She’s one of rock’s most creative songwriters and guitarists. And as for that deep, menacing voice? Well, it totally sends creepy-crawly shivers up the spines of whoever happens to be within earshot. Nick Cave knows all this to be true; it’s why she appears on his 1996 Goth-folk collection, Murder Ballads. So does Tricky, whose 1998 electronica hit “Broken Homes” features her exquisitely haunted singing. Not unlike moody Mark Lanegan (with whom she has worked – see his album Bubblegum), Harvey prefers collaborating with artists more leftfield than herself, like Sparklehorse, Philip Ridley, Moonshake and legendary art-rock chanteuse Marianne Faithfull. Tracking down these under-the-radar gems is more than worth it.

Dave Grohl  

Drummer, singer, guitar player, Rock Hall schmoozer… Grohl is the most promiscuous dude in rock n’ roll. Talk about getting around! Playing drums in Nirvana — one of the greatest outfits of the 20th century simply wasn’t enough. He then formed three super-groups (Foo Fighters, Them Crooked Vultures and Probot) while also carving out time for countless all-star jams and recording sessions. (The weirdest just might be P. Diddy’s “It’s All About The Benjamins (Rock Remix I)”.) Scan the liner notes to the Foos’ mega-smash, Sonic Highways, and you’ll spot more cameos than a Wu-Tang album. But the most over-the-top testament to his love for collaboration has to be the Sound City: Real to**Reel soundtrack. Each of its 11 cuts features Grohl and a different rock stars who span five decades. “Cut Me Some Slack” = Macca + Nirvana. Insane, right?


Elvis Costello**  **

The Imposter may be the dean of rock n’ roll collaborators, but he was slow to accept the title. In the ’80s he worked on a song-by-song basis with Squeeze’s Chris Difford and Glenn Tilbrook, Daryl Hall, Annie Lennox and Paul McCartney (see 1989’s Flowers in the Dirt. But it wasn’t until the following decade that Costello began tackling entire albums rooted in concept-driven collaboration: Juliet Letters featured The Brodsky String Quartet, while Painted from**Memory paired him with pop genius Burt Bacharach. More recently, the absurdly versatile Costello has recorded with The Roots, Allen Toussaint, Jenny Lewis and Marian McPartland. Also, he masterminded The New Basement Tapes, a super-group that set recently unearthed Bob Dylan lyrics to music, resulting in 2014’s Lost on the River**. All hail the dean!


Mark Lanegan**   **

Lanegan isn’t the busiest collaborator on our list (that has to be his pal, Grohl), yet he is the most intriguing. Every rock fan is aware of the singer’s work with Screaming Trees, Queens of the Stone Age, The Gutter Twins and Mad Season, as well as his solo catalog. (The aforementioned Bubblegum was one of the coolest records of the ’00s.) Venture off the beaten path, though, and you’ll stumble upon an odd stash of baroque pop, folk and even electronica. His three albums with Isobel Campbell (formerly of Belle and Sebastian) cast them as a modern day Lee Hazlewood and Nancy Sinatra. Also killer is Black Pudding, a gloomy mesh of avant-blues weaving together Lanegan’s sandpapered voice and Duke Garwood’s shattered fretwork and keys. We command you to explore all of it.

**Honorable mentions:  **

Björk, T Bone Burnett, Jeff Lynne, Jack White, Slash, Chris Goss, Tom Morello, Brian Eno, Beck, Eric Clapton, Chino Moreno, Yoko Ono, Daniel Lanois, Mike Patton, Kim Gordon, Paul McCartney, Nick Cave, Thurston Moore, Jerry Garcia, Thom Yorke