One other line of inquiry for this might be the closely related
"chapbooks"--most often just a few pages long--that frequently dealt
with the same kinds of materials. The Lilly Library in Indiana
has a collection of over 1900 of these from the 18th and early 19th
centuries, with a catalogue that can be searched online with any
Web browser. The URL is http://www.indiana.edu/~libresd/lilly/chapbook/
It can also be reached, along with several other British research sources,
via "SHARP Web," the home page of the Society for the History of Authorship,
Reading & Publishing. That page is at http://www.indiana.edu/~sharp
Patrick Leary
Indiana University
pleary@indiana.edu