r/conspiracy, it always had it fair share of nutjobs but it also had some awesome posts every once in a while in which someone would take a theory and break it down in points with good sources. The comments been even better, the top comment almost always was. Point 3, 4 and 7 have been disproven here, here and here, but 5 and 6 are solid further info here.

Over the years those high quality posts became less frequent and after the ban of td it fully turned into a right wing misinformation campaign with topics like the paradise papers completely ignored.