There are quite a few groups that spawned a successful solo artist, often the lead singer gets more popular than the band. But a group spawning two or more successful solo artists seems less common. A few that come to mind are:
The Beatles: John, Paul, and to some extent George
NWA: Dr. Dre and Ice Cube (maybe Easy-E too?)
Destiny’s Child: Beyonce and Kelly Rowland (I guess she’s successful, I’ve heard of her…)
The Eagles: Don Henley, Joe Walsh
Any others?
Genesis: Phil Collins and Peter Gabriel
The Yardbirds: Clapton, Page, and Jeff Beck.
The Spice Girls - for a given definition of “successful solo artists”. They all charted at one time or another, but seem to be failing the longevity test.
Here are a few more:
Led Zeppelin had Page and Plant go on to success as solo artist.
Fleetwood Mac: Stevie Nicks, Lindsey Buckingham, possibly Christine McVie,
Traffic gave us Dave Mason & Stevie Windwood
Yes: gets very confusing. Its members went solo, returned, formed other groups, join others group and muddled up everything.
Jon Anderson, Rick Wakemen had solo success. Steve Howe had big success in Asia.
Buffalo Springfield launched Neil Young & Stephen Stills who both had both Solo Careers and massive hits with CSN & Y.
Jim
Fleetwood Mac - Lindsey Buckingham, Stevie Nicks, Christine McVie, Bob Welch
Fairport Convention - Sandy Denny, Richard Thompson, practically everybody else
Personally, I can’t name any music by Jeff Beck, Lindsey Buckingham, Christine McVie, Dave Mason, Jon Anderson, Rick Wakemen, or Steve Howe. Maybe you had to be big fans of the group to follow their solo career.
What is your age and primary music interest?
In a very short period you have already seen Fleetwood lists twice.
Rick Wakeman had a fairly big album with Journey to the Canter of the Earth and Jon Anderson is bigger with New Age as a soloist. Steve Howe was big as part of Asia, not so much his very good solo work.
Jim (I will admit to being clueless to Bob Welch’s solo work)
control-z I gotta disagree with you on the Beatles. They were all popular solo artists. Ringo was the first of the band to have multiple Top 40 hits, and still tours to this day with a really big show.
Squeeze - Chris Difford, Jools Holland, Paul Carrack, and Glenn Tillbrook is mildly successful (but puts on a really good show)
Your loss.
Lindsey Buckingham had small-to-medium radio success with “Go Insane” and “Holiday Road,” the latter being featured in National Lampoon’s Vacation.
Dave Mason had a pretty big hit with “We Just Disagree.”
Bob Welch had two hits, “Sentimental Lady” and “Ebony Eyes.”
Those are just the ones off the top of my head that you might recognize.
Monty Python? 
How quickly they forget. :sigh:
Jeff Beck – Jeff Beck Group
Dave Mason – Alone Together
Rick Wakeman – The Six Wives of Henry VIII
All great albums.
How John Mayall’s Bluesbreakers: Eric Clapton, Peter Green, Mick Taylor, John McVie, Mick Fleetwood, Jack Bruce, Aynsley Dunbar, John Almond, Jon Mark, Dick Heckstall-Smith, Don “Sugarcane” Harris, and Harvey Mandel all had success both with groups or as leaders of their own bands. For groups only, add Andy Fraser.
Cream hit the trifecta: All three members (Clapton, Bruce, and Baker) had successful solo careers afterwards.
Blind Faith also had three (Clapton, Baker and Winwood), and Ric Grech also had a solo album.
For the Bonzo Dog Band, Vivian Stanshall and Neil Inness were successful solo acts afterwards (Innes is best known for the songs he wrote for Monty Python), and Roger Ruskin Spear had one solo album.
Steve Winwood and Dave Mason of Traffic have been mentioned, but Jim Capaldi also was a success (in the UK, at least) as a solo act.
The Paul Butterfield Blues Band spawned the solo acts of Elvin Bishop and Mike Bloomfield, as well as Butterfield himself.
The original Blood, Sweat and Tears had both Al Kooper and Randy Brecker having solo careers.
…and Mike Rutherford, of Mike and the Mechanics.
Lindsey Buckingham and Christine McVie both had albums out in 1984 that were pretty poular. Stevie Nicks had an album out in 1983 that still was getting a lot of airplay when Lindsey Buckingham & Christine McVie’s songs were charting, so Fleetwood Mac members seemed pretty ubiquitous to me in the mid-80s.
It was actually how I first came to hear of Fleetwood Mac, believe it or not.
Those three are iffy as far as qualifying. All three brought together All Star line-ups. The members were already famous in thier own right. It is the reason I did not mention CSN&Y and a few others.
Jim
The Velvet Underground - Lou Reed, John Cale
**Dinosaur Jr. ** - Lou Barlow, J. Mascis
Company Flow - El-P, Bigg Jus, Mr. Len
the Wu-Tang Clan - nearly every member has gone on to enjoy more solo success than they enjoyed as part of the conglomerate; notably Ghostface Killah, Method Man, the GZA
Beat Happening - Calvin Johnson, Brett Lunsford
Tangerine Dream - Edgar Froese, Peter Baumann, Klaus Schulze, Christopher Franke
Can - Jaki Liebezeit, Holger Czukay, Irmin Schmidt, Damo Suzuki
The Smiths - Johnny Marr, Morrissey
Both Ronnie Montrose and Rick Derringer played with Edgar Winter and then moved on with success although, of course, Derringer had already had a #1 prior to.
Two, actually. I think the better known one is his first, Electric Shocks. The follow-up, Unusual, is essential if only for the Rutles-worthy song title “Shove Off Shostakovich.”
New Editon Johnny Gill, Bobby Brown and Ralph Trevant