"Sweet Dreams" is a commonly used phrase to wish someone a good night's sleep. However, there are several other phrases and synonyms that can be used to convey the same message. Some of these include "rest well," "sleep soundly," "pleasant slumber," "goodnight," "sweet slumber," "rest peacefully," and "sleep tight." These phrases can be used not only to wish someone a peaceful and restful night's sleep but also as an expression of caring and affection towards the recipient. Whatever the words, the sentiment remains the same - to express a desire for the person to have a good and refreshing night's sleep, so they can wake up refreshed and energized for the day to come.