Check out the Family History Library catalog. In terms of its library collections, there are no rivals. From this web page, you can search by place, surname, keyword, title, film/fiche, author, subject, and call number. Try all of them. Don’t do actual research with this exercise. Instead just click links and see all the catalog has to offer. Many of these items can be rented for a small fee and viewed at your local Family History Center. You do not have to be a member of the LDS Church to utilize this service. If you write a genealogy blog, tell readers what you found during this exercise, or describe the types of materials you’ve received through this genealogy tool.
Place search is my favorite way to search the FHL catalog. It's the easiest way to find all the material available for a particular county. Make sure to click on the "View Related Places" button in the top right corner after you do your search. If you search for a county, then it will show the towns in that county. The towns will have new and different records than the county as a whole.
The other way I like to use the catalog is through the film search. If you use the Family Search Pilot or Beta sites, often the transcriptions you find there will reference a film number. Enter that number into the catalog and you can find out where the information was taken from and then you are able to order it for yourself.