Players may have seen a boutique named "Angelista's Boutique" and some items named after her:
Her name sounds like a Priest, but her equipment definitely isn't priest-like. There isn't any backstory about Angelista. For the moment nobody knows who is the mysterious Angelista. Some players think that Angelista is probably related to a Blizzard staff member or affiliated with Blizzard. She is also listed in the "Special Thanks" section of the WoW credits.
We hope we will find out more about Angelista soon.