Here are some highlights of what is presently available at the Footnote website...
- Name Index to Civil War (Union) and Later Pension Files 1865–1899
- Southern Claims Commission Records 1870s
- Pennsylvania Archives Series 1625–1880 (presently free to use with registration)
- Naturalization Records Indexes for Massachusetts, New York and Pennsylvania (years and courts vary)
- Some City Directories for Connecticut, Maine, Massachusetts, New Hampshire and Rhode Island
Some of the records at Footnote were digitized from material in the National Archives (NARA). You can read NARA's press release about this at: National Archives and Footnote Launch Project to Digitize Historic Documents