Shears

 are a vanilla tool, used to shear Sheep and obtain Leaves. Shears can be enchanted with the rainbow enchantment to get different colours of Wool from Sheep.

Trivia
At one time after the Dwarven Mines Update, shears enchanted with Efficiency would grant even while not held. This led to players keeping multiple Efficiency V Shears in their inventory, allowing them to instant-mine many things, including Mithril. However, this was quickly patched.