I like Deep Purple but King Crimson, ELP, and Yes were my introduction to psychedelia. Here’s Emerson, Lake and Palmer doing Knife Edge circa 1970.
While not something that I listen to everyday, I have almost everything ELP has ever released including stuff from the last two decades where they have seen a few reunions and partial reunions. None of it is as good as their early stuff, but I do enjoy listening to it occasionally.