Is there an organisation similar to the Illuminati?

I am making a character who is a conspiracy theorist. If the setting were the modern world he would see the touch of the Illuminati on everything that happens, and talk about the secret cabal that rule the world.

Is there anything in lore (5th edition, Forgotten Realms preferably, but any edition and any setting is acceptable) that has a similar theme?

I know there are secret organisations such as the Harpers, but the lore I am aware of doesn’t involve directly trying to control the world through subtle means.

Bonus question if there is no such lore: Is there any lore or organisation that would be directly responsible for ensuring no such organisation could exist?