The whole psych/neo-psychedelia scene is an origin of or adjacent to other stuff I like, but they're movements I haven't spent that much time exploring. Here are what RYM says are some of my favorites that haven't been mentioned.
The Devil's Blood - The Thousandfold Epicentre - psych rock
Dool - Summerland - psych rock
Grouper - Dragging a Dead Deer Up a Hill - psych folk
Jimi Hendrix - Are You Experienced, Axis: Bold As Love, and Electric Ladyland - psych rock
Jess and the Ancient Ones - Vertigo, Astral Sabbat, The Horse and Other Weird Tales, and s/t - psych rock/heavy psych
Master's Apprentices - A Toast to Panama Red - heavy psych
Marissa Nadler - The Path of the Clouds and The Wrath of the Clouds - psych folk
Sir Lord Baltimore - Kingdom Come - heavy psych
Tiamat - A Deeper Kind of Slumber - psych rock