There are several synonyms for the phrase "be well" that can be used to convey good wishes and positive thoughts. One could say "stay healthy" to emphasize the importance of well-being. Another alternative is "take care", which not only expresses concern but also encourages cautiousness. "Stay strong" implies resilience and the ability to face challenges head-on. Similarly, "be safe" emphasizes the importance of protecting oneself from harm. Additionally, one could use "farewell" as a more formal and traditional way of bidding someone goodbye while hoping for their well-being. These synonyms offer various options to express sincere wishes for someone's health and happiness.