Hammer: Used to smash rocks in outside world.
Handy Glove: Makes you smash certain kinds of bricks when using your sword attack.
Boots: Gives Link the power to walk across certain areas of water.
Raft: It has one purpose in the whole game. To escort you to the other half of the world.
Whistle: Kills the dreaded water devil and opens up the next palace for you.
Cross: Very useful, it allows you to see ghosts in the graveyard.
Key: What else is it used for except to open lock doors.