A React developer is on record some months ago as saying that as far as he personally is aware, no such patents exist. Further, patents are a matter of public record, and to date, nobody has identified a patent that might cover React.

Of course, a random comment from a React dev on github carries no legal weight, and absence of evidence is not evidence of absence. But so far the picture being painted seems consistent with there being no list of patents at all, secret or otherwise.