Non-Metal SONGS by Metal Bands

Agalloch - The Misshapen Steed
Opeth - Harvest\Windowpane - Amazing songs
November's Doom - Twilight Innocence - Completely different to everything else, and a beautiful song
Jacobs Dream - Mad House Of Cain - This is one hell of a weird song, and it sounds sinister and creepy. Completely different to the rest of the album.
Moonspell - Proliferation - Such an awesome song, kinda fits with the rest of the album, but also sounds very much different.
Vesperian Sorrow - Odyssium - After an entire album of black metal, it finishes with an acoustic-styled song with female vocals. Completely different to the rest and very much unexpected.
As in, Dimmu Borgir didn't actually do the intro... it was the Prague Symphony Orchestra. I'm sure the band could do classical music, but not on that level.

Apocalyptica does count as metal, yes? When they're not just a cover band or featuring subpar artists singing on their songs anyways... they've gone a bit downhill lately.

Then looking at their Reflections album...
Apocalyptica - Cohkka

Orphaned Land - The Calm Before the Flood
At The Gates - Into the Dead Sky
At The Gates - The Flames of the End (I couldn't decide between just one. although SotS isn't hailed as their finest, it is a hell of a way to end an album.)
Nile - The Infinity of Stone
Moonspell - Sons of Earth