The Legend of Zelda: The Mystical Seed of Courage

From Zelda Wiki.org

Box Art From The Mystical Seed Of Courage

The Legend of Zelda: The Mystical Seed of Courage (sometimes refered to with the fanon title Oracle of Secrets) was a third game that was originally going to released with Oracle of Ages and Oracle of Seasons, to form the Triforce Trilogy. It was cancelled due to issues involving how the games connected to each other.

Known Facts

This game was to feature Farore as the game's Oracle.
This game was to feature time travel, and puzzles involving the time of day.
Oracle of Ages was originally going to feature puzzles involving colours. When The Mystical Seed of Courage was cancelled, Oracle of Ages took the time travel theme.
No screenshots of this game exist.
The box was likely going to be green, with the game titled Oracle of (*). While one would assume it likely that it would be Oracle of Secrets, it is debated whether Farore would've gotten that title if she would've gotten her own game, as that game wouldn't have been about "secrets".
The game would have somehow involved the Book of Secrets.