Within the Library of Congress Classification system, dramatic works are filed country of origin, along with novels and poetry. Because of this, plays are scattered throughout the P sections. Here at the University of Winnipeg, we have created a separate section for plays where they are all filed together (except for the plays of Shakespeare, which remain with other Shakespeare-related works). A search for "UW DRAMATIC WORKS COLLECTION" (using "B8" as the Location Code) will produce a list of thousands of these plays. In an advanced search, you can combine this term with specific playwrights, e.g.,
B8: DRAMATIC WORKS COLLECTION au: shaw
It is also possible to limit one's search to a particular play publisher, e.g.:
B8: DRAMATIC WORKS COLLECTION kw: methuen