So for various reasons I have a list of every MD5 for images hosted by Sankaku Complex and/or Danbooru.
Turns out that out of Danbooru's 2160674 non-banned and non-deleted images, Sankaku Complex has all but 6233 of them (99.7%).
Is this a known thing? Not saying there's anything wrong with it, just curious if it was common knowledge or if there's a story behind it. They also have ~84% of Yande.re's stuff.