27. Exhorder - The Law - 1992
People retroactively call this groove metal, but this is really just a brutal thrash album. It does have some serious grooves though, with killer riffs to make them hit like a ton of bricks. One of the most extreme thrash albums you'll ever hear. What most groove metal bands get wrong is a lack of energy, but Exhorder's mastery of thrash dynamics keeps this from ever getting stale. And just check that bitchin' Black Sabbath cover.