These are more trippy documentas with super deep concepts. I can literally feel my brain expanding. Especially with "Waking Life". but the other ones are good too http://www.explorecreatelive.com/documentaries-that-will-make-you-think/
Even though it's a true story or whatever, the movie Howl with James Franco about Ginsberg has these visuals that are crazy trippy mixed in with the black and white scenes. It's also a good story.
I feel like peoples ideas of trippy are getting a bit mixed up. While enter the void is really crazy and has a strange style, it is not something you want to watch while tripping, due to all the depressing and scary, grungy, crazy shit that goes down, but it is "trippy," I guess. Then there is stuff like 2001 Space Odyssey, it's also "trippy." But 2001 is fairly light story wise and is really fun to watch tripping. If you like space documentaries, watch 2001 for sure. So I guess i'm just tryin to say that a movie can be very trippy, but you don't wanna watch them all while tripping. And Pan's looks fucking amazing I can't keep my eyes off of that movie.