Hmm there's so many good ones, it's hard to choose. But I'll try:
Amon Düül II - Phallus Dei
Tangerine Dream - Phaedra
Donovan - A Gift From A Flower To A Garden
Pink Floyd - The Piper At The Gates Of Dawn
Pink Floyd - A Saucerful Of Secrets
Justin Heathcliff - Justin Heathcliff
Cream - Disraeli Gears
Pink Floyd - A Saucerful Of Secrets
Magna Carta - Lord Of The Ages
King Crimson - In The Court Of The Crimson King
Led Zeppelin - IV
Bob Dylan - The Freewheelin' (is it psychedelic?)
John Fahey - Fare Forward Voyagers
Arzachel - Arzachel
Kyuss - Welcome To Sky Valley
Tool - Lateralus
Jefferson Airplane - Surrealistic Pillow
Flower Travellin' Band - Satori
Ozric Tentacles - Waterfall Cities
The 13th Floor Elevators - The Psychedelic Sounds Of
The Doors - The Doors
Well also Callisto - Noir, Red Sparowes - At The Soundless Dawn, and everything by Godspeed You Black Emperor. Though I'm not sure you can call them psychedelic...