Epistlers are those who write letters or epistles. There are several synonyms for this word, each with their own nuance of meaning. One alternative term is correspondents, which implies a back-and-forth exchange of letters rather than just one-sided communication. Penpals is another synonym, which suggests a more informal and perhaps international relationship. Letter writers is a simple and straightforward option, while missive senders gives a more formal and business-like tone. Some other synonyms for epistlers include corresponders, dispatchers, and note-writers. Regardless of the specific term used, all of these words refer to people who engage in the art of letter writing.