Quote Originally Posted by Fizban View Post
Do you mean organizations, or Affiliations? I quite like the Affiliation rules and would love to see some, but I don't think that's actually what you're going for. Affiliations include ranking and benefits, as introduced in PHB2 and used extensively in Complete Champion (including the mentioned Paragnostic Assembly), with a couple more lost in other books.
I usually turn to Power of Faerun for my D&D organizaion building fun but that's because those rules are built for use with Leadership.