Here are some of the groups relative to Hellboy's travels...

. Order of the Fly
. Sonnenrad Society
. The Danres Society
. NYC Explorers Club
. The Osiris Club
. Silver Lantern Club
. Heliopic Brotherhood of Ra
. Knights of the Silver Star
. Knights of Abjdos
. Organization of American States (O.A.S.)

Can you share any other groups that are mentioned in Hellboy's universe?