A "gift from on high" is often used to describe something that is miraculous or providential. Synonyms for this phrase could include "divine blessing," "heavenly boon," or "godsend." These phrases all imply that the gift in question is something that has been bestowed upon us by a higher power or force, and that it is something that is beyond our own control or influence. Other synonyms for "gift from on high" might include "miracle," "windfall," or "stroke of luck." All of these phrases convey a sense of gratitude and awe towards the gift in question, as well as a recognition of its power and significance.