Aside from Stargazer and Ignivomous, both of which bore me, I'd say you have most of it covered already. The two D666 albums you named are the only ones worth hearing, if only for their energy and machismo.
Additionally, what little you haven't covered has already been named by others. Dead Can Dance alone cements Australia as having contributed quality music to the world. SadEx is a sore omission, within the very narrow aesthetic scope it occupies - no beauty or majesty, just razor-wire filth and inebriated hatred. And I like everything Portal's made so far. Midnight Odyssey is also good. Spear of Longinus is a band that I respect immensely, but to be honest, enjoy very little; their music just doesn't speak to me. Not when taken on its own, anyway; when heard in light of their frontman's interviews(best metal interviews I've ever read bar none, by the way), the music does take on a new dimension.
There may be some painfully obvious exemptions that I'm unforgivably forgetting, but from the top of my head the only names I can think of to add to the list are Sacriphyx, Abramelin, and Martire - and, with somewhat less certainy, Misery, Nazxul, and Lord of the Command. Sacriphyx does the Greek style of black metal, and does it well; Peninsula of Graves and the song from their split with Stargazer are both immensely Romantic works. Abramelin's first album is not unlike Blood's O Agios Pethane in execution, although with longer songs; punchy grindcore riffs strung together into a cohesive unit, so its initial impression of blockheaded fury belies a deeper innate understanding of musical structure that just so happens to sound vitriolic. Martire is a bit of an odd duck, I'm actually having trouble thinking of a way to describe it; it's probably best just to listen to their self-titled EP without any prior description.
The other three are not as good as any of the names already mentioned, but have their own value nonetheless. Misery had a very unique brand of death metal that reminds me a bit of Adramelech's Pure Blood Doom - not in style or structure, as it sounds entirely different, but rather in just how entirely inorganic of a world it conveys. Nazxul's melodic black metal is a good listen, although I wouldn't rate it higher than a low B. Lord of the Command is the weirdest of the bunch, and in fact I can't say for certain if I even like it or not. All I know is that I find myself returning to it every so often; it's very weird and confused, but I not in a way that doesn't make sense. They only made two short demos, so you might as well just try them out yourself and see what you think.