Here are some of her notable works:
History:
* "The Life and Writings of Mirabeau B. Lamar: President of the Republic of Texas" (1934): This is her most famous work, considered a definitive biography of Lamar.
* "Anson Jones: Last President of the Republic of Texas" (1926): Another biographical work, focusing on the last president of the Republic of Texas.
* "Trailing the Spanish Treasure: The Story of the Treasure Ships of Spain" (1930): A historical account of the Spanish treasure fleets.
* "The Lone Star State: A History of Texas" (1917): A comprehensive history of Texas.
Fiction:
* "The Lone Star" (1908): A historical novel set in Texas.
Other Works:
* "A History of the First Republic of Texas: A Handbook for Teachers and Students" (1913)
* "The Texan of the Revolution: A Historical Tale of Texas" (1917)
* "The Romance of the Republic of Texas" (1932)
Gambrell also contributed articles to numerous newspapers and magazines. Her work is often cited as valuable for its historical research and detailed accounts.