A fan letter is a written communication expressing admiration or support for someone. However, there are many synonyms for fan letter that you can use to express your love, adoration, appreciation, or approval. Some of these synonyms include fan mail, love letter, appreciation letter, support letter, fan note, admiration letter, praise letter, congratulatory letter, thank you letter, cheer letter, and encouragement letter. Regardless of the synonym you choose, the intent is the same - to convey your feelings to the person you admire and show your support for their work or achievements. So, whether you are a fan of a celebrity, an artist, a writer, or a sports star, you can use these synonyms to express your admiration or support in a unique and creative way.