Sodom, Kreator and Destruction. Not only because they took piece from the German thrash scene, but their music had similar quality level as well.
Their first full-lenght album, "Golem" was already heavier in sounding, than most of the well known German thrash bands, because they involved death metal influences too. But in speed and intensity they were behind the others, so maybe this way they "lost the brutality campaign". In musical themes they showed higher diversity too, not speed and brutality was the only thing they had interest to. Mid speed, societal and political topics were same common at them even from the beginning, so in some way they were not a typical extreme band in the '80s European thrash scene. International breakout came for them after "Urm the Mad", which album showed more interesting features of their developing style.