Tangerine Dream - Amazing band. Difficult to get into due to their immense and quite diversified discography. You must try before giving up: Electronic Meditation (dark experimental guitar work; unlike any other TD album that I know of), either Alpha Centauri or Zeit (the Kosmische albums), either Phaedra or Rubycon (both of which are their most popular but I'm personally not a big fan of any) and either Force Majeure or Tangram ('80s sound, closer to traditional rock). They're worth it.
Van Der Graaf Generator - Another amazing band. More consistent than TD but none of their albums stun me as much as the first 3 TD albums. I don't know if it's Hammill's vocals you have a problem with or if maybe you've only heard Pawn Hearts but otherwise I don't see why someone who loves classic prog like you seem to do would not like VDGG. I suggest listening to Godbluff if you have trouble getting into them, if any is going to make you love them it's this one.The Least We Can Do is Wave to Each Other and H to He Who Am the Only One are lighter and Pawn Hearts is perhaps the most ambitious beast of all classic prog.
IQ - zzzzzzzzzzzzzzzzzzzz