If you want to look at the library's physical collections, here are a few tips:
The Library of Congress Classification System groups plays by country/language, time period, and author name. There are also special sections within these that are specifically for collections of plays. Use this link to help narrow your possibilities.
Here are some other call number ranges that might be useful:
Searching for a specific playwright or specific play?
No specific play/playwright in mind?
If you're looking for shorter plays, try searching the catalog for one-act, ten minute, or short plays. Also, the Humana Festival publishes the complete plays from each year and there are some short plays mixed in, but they are not grouped together.
The styles mainly used for Theatre & Dance are:
However, you should follow the instructions given by your professor, editor, or journal first. See the Citation Resources page for more detailed information on citation styles.