Tetra appeared in The Legend of Zelda: The Wind Waker as a respected pirate of the Great Sea. After getting attacked by the Helmaroc King, she is dropped onto Link's home island on his birthday. Link sets out with her to fight the new evil. Later in the game, Tetra was revealed to actually be Zelda.
In The Phantom Hourglass, Tetra, sailing with Link, was kidnapped. Link goes on another adventure to rescue her.
In the Super Smash Bros. series
Also, when the disk was hacked, Toon Zelda/Tetra was revealed as a partially completed character.