As you've requested in comments to "10 Bands That Don't Rock Anymore", here's a list of artists who have made the reverse change in their careers and started playing rock music.
7. Vanilla Ice
His first album "To the Extreme" released in 1990 (actually, it's re-recorded 1989 album "Hooked") has spent 16 weeks at the top of the Billboard 200 and sold 15 million copies worldwide. Thanks for the Ice Ice Baby.
After not a very successful album "Mind Blowin'" Ice started a friendship with producer Ross Robinson, who had become known for producing such bands as Deftones, Korn, Limp Bizkit and Sepultura. So in 1998, "Hard To Swallow" was released. The sound on this album has changed more to rap metal and nu metal. Reviews of the album were mixed to negative. A reviewer for the New Times in Los Angeles referred to the album as "stupid, exploitive, derivative rap-metal by the man who once did nearly irreparable damage to hip-hop."
6. Kate Nash
Kate Nash is an English pop singer and songwriter. Her debut album, "Made of Bricks", peaked at number 1 in the UK and number 36 in the US.
In 2013 Kate released "Girl Talk". Dropping the slick production of her previous album, Nash jumps headlong into a punk- and garage rock-influenced aesthetic that has more in common with such distortion-heavy guitar bands as the Raveonettes, the Kills, and the Dum Dum Girls.
In 2007, MGMT released their debut album "Oracular Spectacular" with such hits as "Kids", "Electric Feel" and "Time to Pretend". Bet you have heard these songs on the radio several times a day back then. In 2012, Rolling Stone ranked the album at number 494 on its updated list of The 500 Greatest Albums of All Time. AllMusic called Oracular Spectacular's tracks "some of the catchiest pop songs to come from NYC since the turn of the millennium".
But in 2013, MGMT presented their self-titled album with more psychedelic rock sound. According to review aggregator website Metacritic, the album received an average critic review score of 62/100, based on 37 reviews, indicating generally favorable reviews. This album might be bad news for radio DJs out there praying for another "Kids" or "Electric Feel".
MGMT is currently working on a new album called "Little Dark Age". Will see soon what it'll sound like.
4. Dir En Grey
Although Dir En Grey were never a pop band, they've changed their sound from pop rock/alternative rock to progressive metal. Some tracks of their debut album Gauze demonstrated a clear pop appeal, which was abandoned in favor of a more progressive sound on the next albums, "Macabre" and "Kisou". Since the release of their album "Uroboros" in 2008, Dir En Grey have been frequently described as progressive metal. "Uroboros" and their 2011 album "Dum Spiro Spero" express a remarkable difference from previous albums, with critics noting that their sound on these albums bears almost nothing in common to their earliest work.
Myrkur is a one-female band, started by Amalie Bruun, a Danish pop singer when she decided to play black metal. Probably the weirdest participant in this list.
The original line-up of Ministry consisted mainly of Al Jourgensen (vocals and guitar), Stephen George (drums), Robert Roberts (keyboards), and John Davis (keyboards), although with a few personnel changes, the band's image would begin to focus more on Jourgensen and Stephen George. Ministry's original sound was essentially new wave synthpop. Their first LP "With Sympathy", was issued on Arista Records in 1983 and hit the upper '90s in the Billboard 200.
In 1986, Ministry released the second LP "Twitch". The album stepped away from the pop-oriented form of their previous record "With Sympathy" and moved toward a darker, more aggressive sound in the form of EBM.
Finally, in 1988 the band has started mixing industrial with rock, as opposed to more electronically influenced previous albums, although only the first three tracks use guitars extensively.
In 2016, Al Jourgensen cited "The Land of Rape and Honey" as his favorite Ministry album. Bands like Fear Factory, Linkin Park, Slipknot and Nine Inch Nails call this album as significant influence.
I was not saying that Pantera was a pop band, don't beat me. But, hey, playing glam metal and then turn into groove metal. I couldn't help adding Pantera to this list.
Despite being a standard glam metal band at the beginning of their career, the band members perceive themselves to have had an uncompromising career in which they never "sold out" or gave into trends. This is most noticeably highlighted in the themes and title of their 8th album "The Great Southern Trendkill". Phil Anselmo said:
"We've survived every fucking trend - heavy metal, 'grunge metal', funk metal, rap metal - and we're still here. We put everyone on notice that we don't fuck around. Our fans know we're true right down to the fucking core."
Know more artists that turned from pop to rock? Feel free to post them in the comment section below.