Which is also to say, if you know of any, for the love of god tell me about them
Not exactly what you're after but I am put to mind of small and adjacent examples, i.e. in The Chronicles of Thomas Covenant, the reader is told again and again that the Bloodguard are supernaturally incorruptible ("We are the Bloodguard: you cannot cast doubt upon us.") People within the world believe this. It is untrue.
Intentional negative space also makes me think of a lot of TTRPG worldbuilding stuff, where answering questions with "No-one knows for sure" or "That has been lost to history" is both efficient and dramatic.
Good post, thank you for the thoughts.