I would say most of the completely organic (I know I could be opening a tin of worms here but I know what I mean) hallucinogens, such as psilocybe, salvinorum, mescaline, DMT, atropine/scopolamine etc. are more 'sacred' because they have a longer history of use. If you believe in the collective unconcious, then you'll understand when I say being on these chemicals (I'll omit scop/atropine- haven't used them) feels 'old', like your walking into a party/doof thats been going for thousand of millions of milleniums. Nothing gives me a feeling of the ancient like salvia though. Using these sort of things gives the sense of tapping into old wisdom, accumulated and stored- whether in the substance or our brains, I don't know.
Chemicals that push the mind out, beyond sheer introspection or physical pleasure, seem more mystical to me- i equate mystic experiences as those that are utterly tangible yet unspeakable, events that have no reality because there is no words or will never be words to describe the actual events or whatever it is- pure conceptual thought and feeling.
DMT and salvia, whilst not inspiring great works of architecture on my behalf, certainly erected great monuments in my mind.