There are several synonyms for the phrase "pat someone on the back," which is often used to express praise, encouragement, or approval. One alternative is to commend someone, which can include acknowledging their accomplishments or expressing admiration for their efforts. Another option is to congratulate someone, which typically refers to offering well wishes for a specific achievement. Similarly, one might offer words of praise or appreciation, which can be a more informal way of expressing approval or admiration. Alternatively, one could offer encouragement or support, which can be a way of bolstering someone's confidence or offering assistance during a challenging time. Ultimately, there are many ways to express positivity and affirmation, and these synonyms provide a few alternatives to the familiar expression of patting someone on the back.