Iron Boots
From Zelda Wiki.org
Iron Boots are an item found in three of the four 3D Zelda games. Although they do not seem like a very intuitive item, they have a variety of uses throughout the games. They can be equipped to make you extremely heavy, enabling you to walk along lake bottoms, force your way through tough wind currents, hurt enemies, and exclusively in Twilight Princess, walk along walls and ceilings using magnetic forces.
Ocarina of Time
They can be found in the Ice Cavern in Ocarina of Time. When equipped, they make you walk very slowly due to their extreme weight, but you can go at the bottom of lakes and other sources of water, and if you do, you will not walk slowly. Remember to wear the Zora's Tunic, or you will drown after around one minute. They are extremely useful in the game for getting through the Water Temple, although they are completely unnecessary for experienced players. They are also very useful in the Shadow Temple, as they enable Link to walk against the fan currents.
The Wind Waker
The Iron Boots are also found in The Wind Waker. Although you cannot wear them in water, you can use the Iron Boots to avoid being influenced by the wind, making them required for the Wind Temple. They also allowed you to activate a springboard.
Twilight Princess
They once again make an appearance in Twilight Princess. They are found in the Mayor's house in the village of Ordon after defeating him in a nice, friendly Sumo Match. They are used to ward off the Gorons on your way up Death Mountain, as well as the secret to defeating the Goron Elder, Gor Coron, granting you access to the Goron Mines. They are also need to defeat the confused Dangoro, and Fyrus, the temple's boss and the Goron's patriarch, originally called Darbus until being corrupted by the Fused Shadow.
