Albert Hofmann. Really the obvious choice I think (as many others have already pointed out).
Paschal Beverly Randolph. Dude firmly believed that through the use of drugs, ordinary folks could have genuine visions of the heavenly realms, communicate with angels, etc.: "The use of Hasheesh, Napellus, Opium, the juice of the Indian Soma, or Egyptian Lotus plant, besides many other narcotics of special virtues, constitute a large portion of the preparatory exercises, by which Oriental Ecstatics produce their abnormal conditions," and "there is no doubt that Confucius, Pythagoras, and his disciples [...] and mystic brethren of all ages used it to exalt them." At one point America's biggest importer of marijuana. Abolitionist, too, hung out with Lincoln. All-around swell motherfucker.
Less "yay drugs!" and more "remember your OPSEC kids," maybe that Jaqen H'Ghar fellow from Game Of Thrones? Capable of changing his face and identity at the drop of a hat, always one step ahead of L.E., smirkingly doling out cryptic advice to the youngsters, and smoothly helping out noobs in need. (I'm intentionally keeping it vague for those who haven't seen / read it yet.)
Silvia Saint. I mean look, just a classic pornstar, hella pretty gal, everybody loves her, who could possibly complain?
I think Beaker the Sesame Street character would be great. He has many great expressions. https://matthewhyde.files.wordpress.com/2011/09/20110924-124903.jpg