Jar

Debuting in A Link to the Past, ceramic pots or jars are found in most games in the Zelda series. When broken, they reveal items such as Rupees, hearts, fairies, bees, arrows, bombs, water, and even Ooccoo. They can be found in houses and dungeons, and sometimes they look like vases. Pots can be broken by throwing them, rolling into a wall with a shelf that houses them, or striking them with a sufficiently powerful sword. They are not to be confused with Magic Jars.

Water Pot
This is just a large pot filled with water. Used in The Wind Waker for temporarily cooling and solidifying lava so Link can travel across safely. These are found mainly within Dragon Roost Cavern. In Four Swords Adventures, water pots are found in houses and caves. They are used on The Mountain Path to extinguish swaths of flames.

Water Pot serves the same purpose as Mega Ice from Oracle of Seasons and Spirit Tracks and Water Fruit from Skyward Sword.

Expensive Jar
Found only in The Wind Waker in the House of Wealth, these are shiny blue and white jars that decorate the first floor. If Link breaks one of these jars while Mila's Father owns the house, he will not be allowed to leave until he pays the necessary amount of rupees needed to replace the jars. After ownership of the auction house passes to its new owner, after Link defeats the Helmaroc King at the Forsaken Fortress, Link can break as many of these pots as his heart desires without a single fine; they will be replaced the next time he enters the mansion, curiously.

Flying Pot
In Ocarina of Time, Majora's Mask, The Minish Cap, and Phantom Hourglass, there are Flying Pots that come alive and fly at Link in order to attack him. When broken, these pots contain items such as rupees and hearts.

Warp Jar
Featured only in The Wind Waker, Warp Jars allows Link to warp to other unblocked warp jars in a dungeon. These are very useful for quickly navigating a dungeon.

Trivia

 * In A Link to the Past, jars are replaced by skulls in the Dark World.
 * Link's fascination with breaking jars is made fun on in Twilight Princess when he examines them eagerly in Hena's Fishing hut, and he can even be expelled from the fishing hut after multiple attempts to break those pots with roll attacks into the wall.
 * This jar-breaking tendency is also played upon in The Wind Waker, where Link is charged 10 rupees for each of Mila's Father's china jars that he breaks