If you wanna explore outside Slayer & Exodes Heres few you should try:
Vio-lence, Dark Angel, Heathen, Explict Hate, Evildead, Sacrifice, Razor, Toxik, Exumer, Living Death, Tankard,Dorsal Atlantica, Acid Reign, Exciter, Mutilator, Violator, Slammer, Mantic Ritual & Gama Bomb.
And if you havent heard most well known like Testament, Sepultura, Sodom & Kreator etc, you should give them a try
You can get started by these
Oh yeah the top five is quite impossibl to say but lately Kreator, Vio-Lence, Nuclear Assault & Exodus have been kickin the shit out of me.
E: And finnish thrash legend Stone ofc