I'm unfamiliar with a lot of them, but I've made a lot of them myself.
When you have downtime and you drink for free when working...you're going to experiment. Most are awful, some are great...as that article states, though, don't expect every barista to know every one of those...especially when names change from store to store and most of them are just stumbled upon by accident. It's not a secret menu, it's just combinations of stuff that's readily available.
The Coffee Bean & Tea Leaf tried to do the SoCal thing and introduce a secret menu last year...the idiocy involved of trying to promote something that's supposed to be a secret was just baffling and within two months the only drinks that were on that menu were the ones that no one ever drank and never should drink (do you want a caramel con panna? No, you do not, they're ****ing awful).
My favorite was a creation of my own so vile that it was used as an initiation right for at least a few years
after I left that store...the Jelly Belly latte...which had one pump of everything and tasted like a handful of those purposefully disgusting Jelly Belly jellybeans. I'd say it's amazing that we actually had a few customers order it, knowing full well what it was...but then again people also buy those awful jellybeans knowing that they're disgusting so...people are idiots.