Learning about the New World Order was for sure the biggest and most eye opening conspiracy theory for me. Then I realized it wasn't a "theory" at all. Next to that was secret societies such as Skull and Bones and Bohemian Grove. Then it was 9/11. Then Theosophy / the New Age Movement / Ascended Masters / Blavatsky / Lucis Trust publishing all of the U.N.'s documents. And the biggest baddest craziest sounding conspiracy theory that I subscribe to is Project Blue Beam and/or Fake Aliens to bring in a global religion. Yes, this WILL happen and I hope it happens in my life time so I can see the hologram show.
Of course also, Project Monarch, Pizzagate, SRA, Crowley, Illuminati / Freemasonry symbolism, Mystery Babylon sun worship at the Vatican etc..