Weapons are seen many times throughout the series, below are a list of them.
Thief, and Black Mage's weapon of choice is a knife. Black Mage personally calls his knife, his "Stabbing Knife" which he, obviously, uses to stab his foes, Fighter, and Black Belt. (The latter he actually stabbed to death once.) Thief is rarely ever seen fighting, so his knife is used mostly for smuggling.
Fighter, and Red Mage's weapon of choice is a sword. Fighter is known mostly for his love of swords, and is trying to invent a type of sword called "Sword-Chucks". Like Thief, Red Mage is also rarely seen fighting that much, but he also has a sword that he uses.
White Mage often uses her hammer to bash in Black Mage's skull whenever he gets too suggestive of his actions towards her.
After a long quest to save the world from an intergallactic fiend, the True Warriors return to Corneria each weilding powerful and legendary weapons. Thief then steals the weapons so that they may use it to kill Chaos. Little did Thief know that the weapons punished anyone without a pure heart, which meant only Fighter could wield them. Eventually, Fighter sells all of them (except the swords.)