List of the most famous Operetta operas, listed alphabetically with photos when available. This list contains popular examples of operas of the genre Operetta, and contains information such as what language the opera was composed in. If you want to know more about these historic Operetta operas you can click on their names for even more information. Any notable operas in the Operetta genre should be listed below, so if you're an opera lover use this list to find a few that you've never heard of. List includes The Merry Widow, Cagliostro in Wien and more.This list helps answer the questions, "What is Operetta?" and "What are the best Operetta operas?"