These kind of groups can be found in the whole world, and they are mostly underground. This genre is too "metalistic" to me and I always get headache from this. But I still have my favourite in this genre: Silpknot...
I like it because the background music of its songs. Slipknot consists of 7 members: 2 guitars, 1 lead vocals, 5 of them are in the "drum" groups(2 of the drum groups are backing vocals). I love the way that they put percussion made by tin or other metals into their music.
When coming up with this genre, I always think of Aerosmith and sing their oscar-nominated song "I Don't Want To Miss A Thing". The lyrics of the song is blues, and Aerosmith performed it with its metal music, with some scream voices, making the music seems like blues, rock and metal----another mixtures of music.
Nightwish, was famous for Opera Rock, once upon a time. Tarja's singing accompanies with soft metal rock group as well as symphonic music. After Tarja's leave, Nightwish's music is changed. Symphonic metal and folk metal. The only genre it has never changed is: heavy metal. (Nightwish is from Finland)
My all-time favourite is from this genre----Evanescence. Soft metal rock accompanies piano.
Grunge rock was neglected by the public once. The bands of this group: Nirvana, the Hole, Bush and No Doubt. "Don't Speak" of No Doubt is my favourite song.
Green Day is the representative of Punk-Rock!!!!!
Nightwish is in this genre too. But I personally reckon Within Temptation is more closer to Gothic Rock.
Within Temptation is from Holland
Muse is a band which is from this type.