Traffic’s first album was the revolutionary one: Mr. They weren’t the leaders, they were just in the groove like everyone else. Peppers which to me was the first Beatles Psychedelic album. From the less obvious parts of the world, I’d suggest Brazil’s Os Mutantes (1968 self-titled) and Paêbirú (1975, by Zé Ramalho & Lula Côrtes), Argentina’s Almendra (1969 self-titled), Germany’s Neu! (1972 self-titled), Turkey’s Elektronik Türküler (1974, by Erkin Koray) and, also counting for more recent stuff, Sweden’s Commune (2014, by Goat), since Tame Impale wasn’t that good at their prime and had long passed it by the time they made Currents, let’s face it. I’d add Moby Grape, Cheap Thrills and Ogden’s Nut Gone Flake just as easily, though. And, of course, Electric Music for the Mind and Body, The Piper at the Gates of Dawn, Vincebus Eruptum, In-A-Gadda-Da-Vida, Forever Changes and Surrealistic Pillow are all rightful psych classics.
Nice to remember the first Soft Machine and Traffic albums too, since they tend to be best remembered by their later stuff on other genres. Also, Happy Trails, Live/Dead and Easter Everywhere are trippier than QSM, Anthem of the Sun and (believe it or not) Psychedelic Sounds. The Stones were, that one time, but I’m not sure if they stand side by side with all those naturals. That said, neither Hendrix nor Cream nor the Doors nor Aphrodite’s Child were ever thaaat psychedelic. The Byrds aren’t, so historical importance is clearly not the point for the list. But then I’m not sure if the Beatles should be there at all. Not sure about Revolver… if you want a Beatles one, I’d have to agree with this other commenting person that Magic Mystery Tour is their most psychedelic, even if it’s not as innovative. I agree Caravan is missing too, but I’d pick their self-titled debut, since they only got more progressive/pop on further albums. As a lot of people have mentioned, Odessey & Oracle is probably the most striking absence.