The Snow Queen is the titular main antagonist of Hans Christian Anderson's 1844 Danish fairytale of the same name and many of its film adaptations. She is a morally ambiguous witch who possesses cryomancy, the magical ability to manipulate ice and cold.
Add filmmakers and cast the films/shows/franchises (or concepts) that they were rumored, considered, offered, negotiated, turned down, and/or partially contributed before departing. (Please double-check in research.)