Swords are the main weapons wielded by Link on his adventures. There have been many different swords, and few bear much resemblance to one another.
The Kokiri Sword is a short blade used by Link as a child in Ocarina of Time. It is his first weapon in the game, as well. It is also featured in Majora's Mask, where Link brought it with him to Termina.
The Master Sword is the most common blade throughout the series. It is known as the blade of evil's bane, and is highly powerful and can dispel evil. It has appeared in every Zelda game since A Link to the Past except for Link's Awakening, Majora's Mask, Four Swords, Four Swords Adventures, The Minish Cap, and Phantom Hourglass.
The Four Sword is a special blade which housed the spirit of Vaati. When the seal grew weak, Vaati escaped from the blade. The sword has the power to split its wielder into four people. It has appeared in both Four Swords games and in the Minish Cap.
The Picori Blade is a blade given to the Hero of Men by the Minish (Picori) long ago. At the time of The Minish Cap, it was used to seal away evil inside of a chest. Vaati broke this sword in half and released the evils inside the chest. Link was then tasked with reforging the blade, a task which was eventually completed by Melari. It then became the White Sword.
The White Sword has appeared in two different instances. The first was in the original Legend of Zelda, where it was the second sword Link could acquire. Its power was double that of the wooden sword. The second appearance was in The Minish Cap, where it was the strengthened and reforged Picori Blade. It could be infused with the elements to make it stronger and restore some of its power.
The wooden sword appears in several games. The first appearance was in the original Legend of Zelda, where it was the first sword granted to Link. It then appeared in A Link to the Past as the first sword again. After this, it appeared in Twilight Princess as a temporary sword while Link was learning the basics of gameplay.