Of all the albums in my collection, Evergrace was far and away the one that took me the longest to find a single copy of. I ended up buying it from someone here because I never saw it even once after several years of searching YJA and Amazon JP. The thing just doesn't seem to exist anywhere. Contrast with albums like DKC, SMRPG, or Goemon, which while crazy expensive are actually pretty easy to find.
I recently came to know about
this album which seems like it would be one of the rarest out there (if it even is out there). I haven't been on the lookout for it for long, but from what I read on RPGFan, it seems it was only given to employees at Origin. Dunno if it was already brought up here. The album title also makes it a real bitch to search for.