Why bother? Steve Roud's folksong index is now past 100,000 entries. The Roud # also cross references versions with different titles. You can search by title, alternative title, first line, collector, singer, place collected, date collected, Laws #, Child #, +...

There is another song index (Butler's) not yet available, which lists songs in old songbooks, and that is of the order of 100,000 titles also. Roud's broadside ballad index also lists songs in many songbooks.