The following are the items and equipment that can be found in The Legend of Zelda: Majora's Mask. They are categorized by type.
Equipment items are automatically equipped and are mainly swords and shields.
Kokiri Sword
A sword with very little strength and short reach. Link begins the game with this sword.
Razor Sword
Give 100 rupees to the Mountain Smithy and in one day he will forge the Razor Sword. It has two sharp ends which means it does double the damage than the Kokiri Sword. However, the sword can only withstand 100 hits. After that, it becomes the Kokiri Sword. If you save via the Song of Time, the Razor Sword will disappear, and you'll have the Kokiri Sword again.
Gilded Sword
Give the Gold Dust and the Razor Sword to the Mountain Smithy on Day 2 so he can forge it into the Gilded Sword, which can be picked up on Day 3. It is highly recommended that you get this sword before you head to the Western Ocean. To get Gold Dust, win the Goron Race after beating Goht. The Gilded Sword is unbreakable and will remain when you save your game.
Great Fairy's Sword
Actually, this sword is a C-Button item. It has a great range and is powerful, but requires 2 hands to wield. Therefore, you cannot use your shield.
Hero's Shield
This is the standard shield for any outing hero. Press R to defend yourself. A Hero's Shield can be eaten by a Like-Like. Either kill the Like-Like or buy one for 80 rupees.
Mirror Shield
This Ikana Royal Family Heirloom can deflect beams of light and cannot be eaten. You will need it for the Stone Tower Dungeon.
Ranged items are items that can be used from far distances.
Hero's Bow
This is a standard wooden bow that can fire arrows. Arrows can be used to hit switches and damage airborne enemies. The Hero's Bow can also be suited with additional power from these items:
Hookshot
The hookshot can latch on to certain objects (And scarecrows) to propel you to new areas!