Heavy Metal 2000 was awful. There is a new one coming soon, supposed to be return to the original's feel.
The Lord of the Rings Bakshi version, The Hobbit and The Return of the King Rankin/Bass version, Luke is dead on about Laloux, Time Masters is amazing as well.......
most Miyazaki, cept for Kiki's Delivery service(very much for children), should count as shining examples of amazing animated psychadelic fantasy.
some others:
Atlantis, The Lost Empire.
The Black Cauldron.
Explorers.
The Last Starfighter.
Barbarella.
David Lynch's Dune.
Kenneth Anger's Inauguration into the Pleasure Dome and Lucifer Rising.
Enter The Void.
Performance.
Behind the Green Door.
The Visitor.
Altered States.
Pan's Labyrinth.
The Secret of Nimh.
Titan AE.
Pink Floyd's The Wall.
Fantasia.
The Holy Mountain.
The Adventures of Baron Von Munchausen.
Eraserhead.
Wild At Heart.
Lost Highway.
Return to Oz.
Akira.
The Man Who Fell to Earth.
Carnivale (TV series).
Twin Peaks.
and more that I cannot recall at the moment or has already been named in this thread.