In case anyone's wondering, this is the updated list of Knightly Orders/Monastic Orders/Secular Orders that have appeared or been mentioned in DL and by Boney (that I found, I'm not going through all 10k Boney posts, just the ones I remember):
Black Guard, Raven Knights, Order of the Sacred Scythe, Knights of the Vengeful Sun, Knights of the Blazing Sun, Knights of Sigmar's Blood, Order of the Black Rose, Knights Panther, Order of the Black Bear, Reiksguard, Winter Wolves, White Wolves, Knights of Taal's Fury, Longshanks, Order of the Shroud, Fellowship of the Shroud, Dreamwalkers, Andanti, Helhunten's Redeemers, Holy Order of the Templars of Sigmar, Order of the Stone Wall, Order of Guardians, Order of Grungni's Pick, Knights Encarmine, Knights of the Golden Lion, Knights of the Broken Sword, Magisters Vigilant, Knights Mariner, Stormguard, Tsarevich Pavel Society, Priory of the Spear, Knights of the Everlasting Light, Order of the Hammer of Sigmar.
I've excluded Guilds, Companies and Military Regiments for the moment, as I'm making a different list for them. The list is sort of arbitrary, but I hope that when I'm done with the absolute monster of a post that I'm gonna be done with sometime in the next six months, it'll feel like you're a Grey Magister who gets a memory packet unlocked whenever you click a spoiler.