List of Super Mario World 2: Yoshi's Island pre-release and unused content
From the Super Mario Wiki
This is a list of pre-release and unused content for the game Super Mario World 2: Yoshi's Island.
Nintendo marketing department initially pressured Shigeru Miyamoto to have the game use prerendered 3D sprites similar to Donkey Kong Country. The 3D models of Baby Mario and Yoshi used in the introduction are leftovers of this period of development.
The following music sounds distorted in places. They are related to the main theme, which suggests that they might have been used at one point during development but were scrapped. The MIDI data contained might have had parameters changed.