Chapotraphouse

There's many youtube videos on ASOAIF conspiracy iceberg. The very top one is obviously R+L=J, Jon Snow parents being Rhaegar and Lyanna. Many of the more sane predictions are around this level. The mid level contains things like John Bolton is an immortal vampire. There are a lot of theories that rely on "World of Ice and Fire" book, which is a companion world lore book published by GRRM and his editors in 2014 describing other humanoids (webbed feet, Neanderthals, winged man, etc.) and fantastical creatures in regions faraway from Westeros. There's a theory that "squishers" (https://awoiaf.westeros.org/index.php/Squishers) which is the ctulhu-fish people built many of Westeros landmarks, like the actual Hightower (described as built on oily black stone foundation), which is similar to how the book described stones in Asshai. Then the bottom of the iceberg you get borderline shitposts, like Tyrion being a time traveling fetus and "X skinchanged into Y" during "Z".