Before I delve into the Top 20 I wanted to throw in the 2nd of 3 "Bonus" lists.
These are all songs from semi-obscure or totally obscure bands or bands most people on here haven't heard that might interest classic thrash lovers. These were all on my long list when I started making a list and they all missed the cut for various reasons.
Xentrix - No Compromise
Assassin - Nemesis
EXE - Slaughter Disorder
Abattoir - Screams From The Grave
Wargasm - Humanoid
Cancer - CFC
I.N.C - Indestructable Noise Command
Morbid Saint - Darkness Unseen
Indestroy - The Gate
Whiplash - Thrash Till Death