List of Yoshi's Story pre-release and unused content
From the Super Mario Wiki
This is a list of pre-release and unused content for the game Yoshi's Story.
The game's working title was Yoshi's Island 64. The early logo looks similar to the SNES game Super Mario World 2: Yoshi's Island logo, implying that Yoshi's Story was originally planned as a sequel to said game and would have been a title in the Yoshi's Island series.
As seen in early footage and screenshots, there was originally going to be a playable Brown Yoshi and Purple Yoshi. However they were replaced by Pink Yoshi and White Yoshi in the final game Flowers were set to appear in the game, but didn't make it to the final version. Large Shy Guys resembling Giant Shy Guys were going to appear and Bone Dragons were to be purple, flesh-covered dragons rather than bony, undead ones. They also looked less sinister. Also it appears that these flesh-covered dragons would have appeared in a more vibrant looking cave rather than the dark one seen in the final game.
Stage 4-2: The Jungle Puddle was known to be much more menacing, with large bubbles and a Bone Dragon. Jungle Hut also looked different than the final version. Yoshi also used the same noises he did in Super Mario World and Super Mario World 2: Yoshi's Island, likely as placeholders until the voice was decided on.
An unused theme can be found in the game's files. It may have been used for another Page.