The members of German band, Lucifer's Friend including John Lawton recorded an album under the name, Asterix but they changed their name to Lucifer's Friend afterwards just prior to the first Lucifer's Friend album.
Now that's a strange one. Another group started out as Grassroots and then became Grass Roots, although that doesn't count as "before they were famous".
Little Boy Blue and The Blue Boys Dick Taylor Mick Jagger and Keith Richards....left to join Brian Jones and Ian Stewart....but the beginning of The Rolling Stones since it was Mick and Keith The Soft White Underbelly Oaxaca Stalk-Forrest Group....eventually Blue Oyster Cult....sorry cannot add the umlaut over the O!!!!!
Fred "Sonic" Smith had a band called The Vibratones and Wayne Kramer had a band called The Bounty Hunters...they combined under the name The Bounty Hunters...Robin Derminer was to be their manager...but then went to bass briefly....then to lead singer....and changed his name to Rob Tyner ....and came up with the name we know them as MC5 Motor City 5.....this was 1964...in 1965 the line up know as the most radical band on the planet was completed with Michael Davis on bass and Dennis "Machine Gun" Thompson on drums!
All three guys in the Minutemen were in a four-piece band called the Reactionaries. They parted ways with their singer to become the much more conceptional Minutemen, even though George left to play in a new wave band for a spell before returning.
The band variously known as Twisted Kites, Negro Eyes, and Cans Of Piss ultimately settled on REM. The band variously known as The Dick Gas Five, Ashtray Babyheads, and Nine Foot Worm Makes Own Food ultimately settled on the Butthole Surfers.
Bob Marley And The Wailers started off as The Teenagers, then became The Wailing Wailers, then The Wailers, then briefly Bob, Rita and Peter, then were intermittently credited again as either The Wailers or Bob Marley And The Wailers, before signing to Island as The Wailers, but became Bob Marley And The Wailers officially as a means of differentiating themselves when Peter Tosh and Bunny Livingston left the group. Similarly Bob Marley's first two singles were under the names Robert Marley and Bobby Martell respectively. He was more likely to be called Nesta or Robbie by family and friends when he was younger, but settled on Bob after Bob Dylan started getting popular. Both Peter Tosh and Bunny Wailer had changed their stage names too, being known for several years as Peter Touch and Bunny Livingston before switching to their familiar names.
For the Germans: Sunnyglade exchanged a great singer for a mediocre (or in my mind bad) one and became Juli
After the Sloan/Barri-produced group had their first hit with "Where Were You When I Needed You," the other Grassroots changed their name to Love. Incidentally, the Sloan/Barri-produced Grassroots was not initially a real band, but just a studio creation. Once their record hit the charts, Sloan & Barri hired a northern California band called the Bedouins to perform and record as the Grassroots. They soon began rebelling against Sloan and Barri, insisting on more space for their own blues-based material, and were promptly fired. The group with Creed Batton replaced them, and the name was changed to "the Grass Roots." They were never known as the Beat Brothers. That was a generic name that was assigned by Polydor for record labels. There is a legend that the name "Beatles" sounded like "peadle" (supposedly German slang for a male body part), hence the name change on the record, but I once asked a German speaker about that, and he had never heard that word before.
