Wilberforce: The Sorcerer's Apprentice
Nabil Gonem attempted to sell this game to various publishers, who refused it due to the declining C64 market. He sold it himself, but few copies were sold, hampered by a 55% review in Commodore Format magazine. For many years the game was believed lost, possibly unreleased (it was added to the Games That Weren't Website). Ultimately a copy was found in somebody's loft, and uploaded to the internet.
Trivia contributed by Martin Smith.