Well-known is a commonly used adjective to describe something or someone that is familiar or famous to a broad audience. However, if you wish to avoid repetition in your writing, there are several synonyms that you can use instead. For instance, you could use the word renowned to indicate that someone or something is widely recognized and respected. Alternatively, you might use the term popular to describe something that is well-liked and frequently talked about. Other synonyms for well-known could include celebrated, famous, familiar, recognized, distinguished, and reputable. Depending on the context of your writing, each of these synonyms could be a suitable replacement for well-known.