Telescope

The telesope is an item Link's sister, Aryll, gives Link in the beginning of The Wind Waker as a birthday present. Although she says she'll let him borrow it for one day only, he ends up keeping it for the rest of the game.

Zuko, one of Tetras pirates, also has a telescope, very much like the one Link gets from Aryll.

In The Legend of Zelda: Phantom Hourglass, one telescope (that turns out to be kaleidoscope) can be received from Imposter Link, and is returned to its owner, a member of the Ho Ho Tribe.