The Federation Alliance was the accord between the United Federation of Planets, the Klingon Empire, and the Romulan Star Empire to combat the Dominion during the Dominion War.
The first offensive undertaken by all the members of the Alliance was the First Battle of Chin'toka in 2374. The Cardassian Liberation Front bolstered the Alliance to help win the Battle of Cardassia and, ultimately, the war in 2375. (DS9: "Tears of the Prophets", "What You Leave Behind")
After the Dominion War ended, in 2379, two members of the Alliance fought against the Remans at the battle in the Bassen Rift. (Star Trek Nemesis)