If you know the foreign language title of the play that you are looking for, do a title search in BobCat or WorldCat, and limit the results by English language.
It is often worth finding out the title in the original language, since there can be more than one English-language variant. Chekhov's Chaika, for example, has been translated into English as The Sea Gull, The Seagull, and The Sea-Gull. Translators may even deliberately try to find a new translation for a title to distinguish their translation from others. In many cases, however, a title search under the commonly-known English title (Three Sisters) will be successful.
Also in BobCat and WorldCat do an author-title search using the title word "Plays," to see if the play you are looking for appears in an anthology of the author's plays. In most cases, the titles of the plays in a book will be listed in the search results