I think Sodom take the cake. They managed to create some great material including Agent Orange, In the Sign of Evil, M-16 and the lesser known, Tapping the Vein. My favorite album by them is Tapping the Vein, but I feel like Code Red wasn't too bad either.
Early Sodom picture. Tom is the one with the God-awful bowl cut
I love all three but Kreator will always be my favorite of all time. Pleasure to Kill, Extreme Aggression and Coma of Souls are so great. But Destruction and Sodom are both a close second.