Every frame that has a name, whether created by the Blizzard UI or 3rd party addons, has that name added to the global table.
If you're looking for frames in the Blizz. UI you can extract all the UI code from the game use that to find the names.
https://wowpedia.fandom.com/wiki/Vie...interface_code
Using /fstack in-game and placing the mouse over a frame will also give you the name if the frame has one or was created as a key of another frame.