The Flaming Lips are definitely psychedelic. The FL guitarist Steven Drozd has been pretty open about his heroin addiction and claims it improves his musicianship and compositional skills. Unfortunately it is also killing him slowly, as he now looks like a shadow of his former self. In any case I highly recommend the album Yoshimi Battles the Pink Robots, as that is my favorite FL album.
Boards of Canada Music Has A Right to Children is more trippy than Animal Collective but is a great album.
**** Buttons Tarot Sport is also pretty psychedelic, but more intense than Animal Collective.
The Antlers Hospice also has a trippy vibe and is a very good album.
Fleet Foxes are more traditional than Animal Collective, but have a Beach Boys vibe if that is what you are interested in.