One of a few free sites to search the Dawes Rolls: http://www.okhistory.org/research/dawes
See if your ancestor is in print: https://books.google.com/advanced_book_search?hl=en
A FREE newspaper site at the Library of Congress: http://chroniclingamerica.loc.gov/
The Portal to Texas History is terrific: https://texashistory.unt.edu/
Cyndi collects and shares links to databases: http://www.cyndislist.com/
On This Day during the Civil War: http://www.on-this-day.com/cgi-bin/otd/uscivilwarotd.pl
Not free, but I can't resist their new databases: http://www.ancestry.com/cs/recent-collections
Roberta Estes blogs about genealogy and DNA: https://dna-explained.com/
Judy Russell is a favorite genealogist blogger: http://www.legalgenealogist.com/
Free family history books have been scanned/uploaded. Click on SEARCH > BOOKS: https://familysearch.org/