Well, in that vein, the Don’t Quit Your Day Job Players, too. 
The Roches feature songs written by Maggie, Terre, and Suzzy, in various combinations and alone.
In the ORIGINAL version of King Crimson, Ian MacDonald was a bit more equal than the others, but he, Robert Fripp, Greg Lake and Mike Giles all wrote or contributed to songs. In later Seventies editions of the band, Robert Fripp was much more dominant (or, at least, less open to sharing credit). Since the Eighties, Crimson songs have usually been credited to all members of the band, but I’m not sure how much each individual contributes. As best I can tell, Fripp and Adrian Belew get together and write most of the music, then later meet with the other guys, who are allowed to tinker with the songs, or try to take them in new directions.
Dan Peek, Dewey Bunnell and Gerry Beckley all wrote songs for America.
ABBA had Benny & Bjorn. Who are now making more from their grand rights (paid to the writer of a musical’s song every time their songs are sung) Mamma Mia! than they did from ABBA.
AC/DC
Young/Young/Scott or
Young/Young/Johnson or most recently
Young/Young
The Rolling Stones
Tom Petty shared writing credit with Mike Campbell for some songs over the years.
Robby Krieger wrote around half of the songs for The Doors.
Jorma Kaukonen I don’t care,
Jorma Kaukonen I don’t care,
Jorma Kaukonen I don’t care,
My massa’s gone away.
10CC had two songwriting teams – Godley/Cream and Gouldman/Stewart, which also combined in different variations, so all four original members wrote songs.
Emerson, Lake, and Palmer
Mountain – Leslie West, Felix Pappalardi, and Corky Lang shared writing credits in various combinations and with Gail Collins.
Spirit – Songs by Randy California, Jay Ferguson, and John Locke. After California and Ferguson left, Al Staehely wrote the songs for an album or two.
All three members of Teenage Fanclub write songs. In fact, on Grand Prix each of the First three songs is written by a different member and they’re among three of my favorite songs of theirs.
Everybody in Iron Maiden has written songs.
Def Leppard–everyone in the band contributes, and it seems that the best lyrics of late come from Vivian Campbell and Phil Collen writing together. I quite like how everyone’s personal musical styles mesh so well to make their sound.
KISS- Simmons/Stanley 99% of the time, I think.
Soft Machine had songs written by all different members (the group constantly metamorphosized). Those credited include Robert Wyatt, Hugh Hopper, Keven Ayers, Mike Ratledge, and Elton Dean.
Would that be on the album Youth Hostelling with Chris Eubank?
U2.
Everyone supposedly chips in, but even if you discount Adam (bass) and Larry (drums), you still have Edge and Bono, who are a pretty dynamite combination.
And on Howdy!, each member wrote four of the twelve songs. You can even break the album up into four three-song sets, with each of the sets containing one Blake, McGinley, and Love number.
In addition to these four, the Grateful Dead repertoire included at various times songs by performing members Mickey Hart, Keith Godchaux, Donna Godchaux, Brent Mydland, Bruce Hornsby and Vince Welnick.
Then there are the improvised jams, which at various times incorporated real-time composition from all of the above plus Bill Kreutzmann, Tom Constanten, Ned Lagin and Bob Bralove. (Branford Marsalis, too, though he was credited as a guest.)
The band effectively had non-performing adjunct members in Robert Hunter and John Barlow, who each wrote lyrics for many songs over a period of decades of association with the band.
We won’t get into the hundreds of cover versions… 
That’s interesting. I’ve been following them since they were just a duo on the college circuit back in the late 80s and I always thought the chemistry between the two to be critical to their success. I think I heard a solo Page song on the radio recently and I wasn’t impressed. I’ll have to check the new Ladies CD and see how it compares.
As for the OP, I’m a big jazz fan so pretty much everything I listen to depends on the interplay of many different talented soloists and improvisers.
In the rock genre, I like a lot of the Canadian collectives like Broken Social Scene and The New Pornographers. Each of those are like supergroups with a ton of writers/collaborators with their own successful solo careers, yet they all of their contributions seem to gel into consistent and coherent sounds unlike their solo projects.