Here are 25 unreleased SNES games. Some are prototypes while others are near-completion. A couple were released in Europe or Japan in one form or another but their scheduled North American release never happened.
Princess Peach has a long history of Nintendo. She made appearances in several games alongside Mario. She also has her own game called Super Princess Peach on Nintendo DS platform. DidYouKnowGaming has the full story. Super Princess Peach Nintendo DS: