A couple leaks that are only disproven if you assume all new Pokemon have been seen.
https://archive.nyafuu.org/vp/thread/27172920/#27174205https://archive.nyafuu.org/vp/thread/28553772/#28554141The first is from the same thread as
>>27174081 so if he's wrong about the Ice/Ghost snowman (no it's not the crab; Chinese-to-English translation errors are one thing but this guy's English is fine) it's pretty amazing that he managed to quietly squeeze in between a real leaker's real posts AND perfectly predict Oricorio. Admittedly there's also the mistake about Abra but even that seems like a minor mistake compared to the Chinese leak's mistake about how Ash-Greninja evolves.
The second was posted by itself so it's not as easy to confirm, but so far it's managed to guess Ash-Greninja being from the demo, special balls needed to capture Ultra Beasts, and the Alolan Diglett and Geodude lines. Individually these are all possible to guess, but all combined? That would take some amazing luck, especially when the only things apparently wrong are the total number of Pokemon and the Alolan Ekans and Dodrio lines. But again, that's only proven wrong if you assume we've already seen everything.