In S1E13, Lorelai meets Paris and Rory outside the Pastorelli Theater. She tosses them t-shirts and says, “T-shirts for all the girls because I am the Good Witch of the… hey, aren’t you missing a couple kids?”
There are two options for references Lorelai could be making:
The Good Witch of the South, Glinda, is a character from “The Wizard of Oz,” both the 1900 novel by Baum and 1939 film. The most powerful witch of Oz, she rules over the Quadling Country. Glinda is also a character in the 1995 novel and subsequent musical “Wicked.”
The Good Witch of the North, Locasta, is another character from Baum’s 1900 novel “The Wizard of Oz.” She rules over the Gillikin Country.