One that I know about are the Fangshields. Are there any other (canon) organizations like that? And if not (Or not many.) then maybe you have created your own? Fill free to scribe here about it, I need any help that I can get (And I noticed that materials provided by Candlekeep scibes are good quality .). BTW. How did (Or would.) you run such an organization? What goals and tactics would it have? P.S. I would be pleased to read something about 'The Knights of The Unicorn' that Wooly mentioned.
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Don't feed the trolls. Especially the clever ones.
I suggest you read through Lurue's entry in Powers & Pantheons. If has some additional info on affiliated orders and, also, covers the Knights of the Unicorn.