There are many synonyms for the phrase "one-of-a-kind", which means unique or distinctive. Some of the most common ones include: unique, special, original, singular, rare, exceptional, unmatched, incomparable, exclusive, particular, and distinctive. Other synonyms include uncommon, extraordinary, individual, unparalleled, and incomparable. These words are used to describe something that is truly unique, that stands out from the rest, and that may never be duplicated. Whether you are describing a person, a work of art, or a unique piece of clothing or jewelry, there are many ways to express the idea of something being one-of-a-kind in a way that is creative and engaging.