@Monomeeth Consensus last time was not at all, even as community wiki. A blog would be the ideal place for this imo, but as AD blog is no more, I wrote about
hidden features of Sierra on my own blog. Each heading on that page I would have posted as an answer to such a question if there was a Community Wiki ‘Sierra hidden features’ question. If AD blog is resurrected, it could go there, along with iOS 11.