Golden Feather

The Wind Waker
The Golden Feather is the spoil of the Peahat, the Winged Mothula and the Kargarok in The Legend of Zelda: The Wind Waker. If 20 of these are given to the Hoskit on the second floor of Dragon Roost Island, who wants to give them to his girlfriend as a gift, he will give Link a "Thank You" letter and eventually a letter with a Heart Piece inside in return.

Phantom Hourglass
These feathers make an appearance as a treasure in Phantom Hourglass as Helmaroc Plumes. Described as flamboyant feathers dropped by Helmaroc Birds, they can be sold on Mercay Island to the Teller of Treasures for a fixed, random price. They can also be sold to a man on a Traveling Ship for more than 100 Rupees each.