What movie do you consider to be the safest from getting remade/getting a sequel?

With more and more intellectial properties being remade each year, it feels like nothing somebody once loved is truly gone, for better or for worse.

Even films I thought would never ever get a chance at being remade, somehow did, like the "Birth of a Nation" remake from 2016.

What films do you believe to be the "safest" from this happening?