You know I LOVE , Love, Love the National Archives!!
If you are looking for a certain public record held by the National Archives which has been indexed by one of their partners (Ancestry.com, Family Search, fold3, etc.) they have a wonderful index on their web site to give you more information on who has the documents in their index. The list is called “Microfilm Publications and Original Records Digitized by Our Digitization Partners” and can be found under the genealogy section of the National Archives web site.
I find this to be a huge time saver when I am searching for a specific record. To access that wonderful indexing list click the link below to go directly to the National Archives. This is also a great reference to help you find records you may not realize are available online.