Catacombs (Cata, December 7, 2004, then April 1, 2005 in Europe) - Added 5 new classes (Heretic; Vampiir, Bainshee; Warlock, Valkyrie), instanced dungeons (where players entering certain areas get their own private dungeon to hunt in), and new zones and quests with an emphasis on faster and easier leveling.
Labyrinth of the Minotaur (LotM, November 5, 2006, then February 14, 2007 in Europe) - Features include a new race (The Minotaur, however there were 3 types, one for each realm), a new hybrid class (The Mauler), a new RvR dungeon, Mythrians, and additional Champion Levels (6-10).