And what is the main differences between them? Is it like Christianity where there seems to be a couple of main ones and then dozens of smaller ones doing their own thing?

  • There have been several attempts before, to ask this question. I think it's probably better to link to some of those, than to ask another question on the same topic -- unless you want to make this question more specific somehow (to distinguish it from previous questions).
    – ChrisW
    Jul 4 '19 at 11:40

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