I can think of three but the main one that comes to mind is Iron Maiden, They had many line up changes from the time they formed in 1975, but the most significant ones to have an impact on sales and popularity were when they started releasing albums, There 1st Album "Iron Maiden" (1980)Featured Paul Di'anno on Lead Vocals, Clive Burr on Drums, Dennis Stratton on Guitar, Dave Murray on Guitar & Steve Harris (Founder of the band) on Bass.
on their 2nd Album "Killers" (1981) Stratton was replaced by Adrian Smith.
after the release of "Killers" Di'anno left and was replaced by Bruce Dickinson who had just left "Samson" where he went by the name of Bruce Bruce, Bruce's 1st Album Appearance with Maiden was their 3rd Album "Number of the Beast" (1982), it spawned 2 singles that both got into the top 10 one of which was "Run to the Hills" and reached No2 in February 1982.
On the 4th Album "Piece of Mind" (1983) Drummer Clive Burr was replaced by Nicko McBrain.
The band kept this line-up for studio album No 4 "Powerslave" (1984), Album 5 "Somewhere in Time" (1986) and Album 7 "Seventh Son of a Seventh Son" (1988), after the release of "Powerslave" in 1984 they were so popular that they embarked on the world slavery tour which took place for a year and was recorded and released as as their first double live Album "Live After Death" (1985), from this time onwards they toured after the release of every Album.
The next band change was on their 8th Studio Album "No Prayer for the Dying" (1990) where Adrian Smith was replaced by Janick Gers on Guitar, Their 9th album was "Fear of the Dark" (1992), then appeared as the headliners at Donnington Monsters of Rock August 22nd 1992, after the Fear of the Dark Tour Bruce was getting tired of the constant touring that went on for 1 to 1 and a half years at a time, he missed his family and really wanted to work on more solo stuff (he had previously released "Tattooed Millionaire") (while with Maiden)), he announced that he was leaving the band for these reasons and played his last gig with them in September 1993. He decided to get another career in case things didn't work out and so he cut his hair and took pilot training to get a pilots llicensewhich he got,
In 1995 they released studio Album 10 "The X Factor" and Album 11 "Virtual XI" (1998) which both saw Bruce replaced by former Wolfsbane Vocalist Blaze Bailey, Popularity of the band slumped with Bailey on vocals and the band had gone in a different direction dressing in Black trousers & T-Shirts after years of Bruce, Baileys style was hard to get used to, Bailey left in 1999 and later went solo, also in 1999 after successfully releasing 4 solo albums and filling venues with solo tours Bruce returned to the band along with Ex Guitarist Adrian Smith making Iron Maiden a 6 man band for the first time, they went on to release album 12 "Brave New World" (2000) Album 13 "Dance of Death" (2003), Album 14 "A Matter of Life and Death" (2006), They then went on the SSomewhereBack In Time Tour in 2007/08 which was Live After Death for the new young fans who weren't around in 1985, it was released as a CD in 2008 as "Somewhere Back In Time - Greatest Hits 1980 -1989, the tour saw Bruce fly the band to and from each gig in the bands 747 "Ed Force One" it was filmed and released as a Movie in selected Cinemas and later a DVD called "Flight 666" and the actual concert was released along side it as a double live album in 2009 their 15th Studio Album "The Final Frontier" was released in 2010 and this year they released a double greatest hits album "From Fear to Eternity - Greatest Hits 1990 - 2010) to accompanySomewhere back in Time.
They are still going from strength to strength and have plans for a 16th Studio Album.
Another band is AC/DC after lead Singer Bon Scott choked on his own vomit and died he was replaced by Brian Johnston Strangely though he sounds exactly the same and unless you did the research you wouldn'tknow which album featured which singer.