The History of Doom

Seems like there are some Doom experts here; so I'll take the opportunity to maybe learn a few things.
Here is the evolution of Doom as I understand it...(by Doom I mean "Stoner Doom" with Sabbath as the primary influence.)

First Wave-Black Sabbath

Second Wave- Bang (first two); Buffalo (second and third). It seemed to stall out here for awhile. I guess Pentagram was laboring in the underground, and Iommi produced projects like Necromandus and Quartz really only had a song or two that fit. After the Sabotage album there was nothing.

Third Wave- Witchfinder General, period?

Fourth Wave- I'm confused here...I'd guess Ozzy's solo success might have been an inspiration, but I don't know who really got things started here. A Pentagram comeback? The St. Vitas bunch? In here was Count Raven, Trouble, Candlemass, etc. I think Obsessed was recorded in the 80's but not released until later?

Fifth Wave- A continuation of the fourth wave, but it kind of diverged into various strands I guess. Straight down the middle stuff like Sleep or Cathedral; alternative influnenced like Kyuss or Fu-Manchu, and mournful euro influenced stuff like Solotude Aeturnus. I've heard Sheavy, Orange Goblin, Spiritual Beggars etc.; I've heard The Sword, but not Place of Skulls or Spirit Caravan yet.

I'm sure I am missing a lot here, so fill me in...thanks!