I've never heard about rainbows and stuff, at least not for weed. I've heard for some people it increases their depth perception to potentially painful levels, I've heard for some people it makes them feel like they can see with their eyes closed, I've heard for some people it makes daydreams more vivid/accessible, I've heard for some people it makes things feel/appear funnier than they actually are... but for me it's just some slight dissociation, which doesn't exactly manifest as a particularly interesting or impaired experience since I experience dissociation all the time just naturally (thanks to my dissociative disorder).
