A brief and horribly incomplete list of "Secret Societies"; a metanode masquerading as real content.
Catholic Knights
Elks
Fight Club
Foresters
Grand Temple of Maat, The Order of Maat
Grotto, The Mystic Order of Veiled Prophets of the Enchanted Realm
Haida
Illuminati, Illuminatus
Job's Daughters
Knights of Columbus
Knights of Dawn, Les Chevaliers de l'Aube
Knights of the Golden Eagle
Knights of Malta
Knights of Pythias
Ku Klux Klan
Masons, Freemasonry
Modern Woodmen of America
National Ancient Order of Hibernians
P.E.O. Sisterhood
Orange Order (ryano)
Rosae, Rosicrucian, rose-croix
Skull & Bones
Templar, The Knights Templar
Priory of Sion
There are more secret societies, though I haven't found any other information as of late. An interesting resource for some one the more esoteric groups is the reproductions of the 1900 Sears Catalog, which sold a large variety of secret society insignia. Secret Societies reached their peak around the turn of the (previous) century, when it was not uncommon for an individual to be a member of more than one of them, although most of those societies were conjured up and not actually old and grand as member were led to believe.