'60s: The Nice, Procul Harum, Soft Machine, Caravan, Can, Van der Graaf Generator. One could make a case for Frank Zappa and early Jethro Tull as well.
'80s: Marillion, Pendragon, IQ, Saga. King Crimson are back. Prog-metal takes off with the likes of Queensryche and Voivod.