4. Generation X (1996)
In 1996 Fox Channel aired a TV movie that was the first live action adaption of the popular X-Men comics, Generation X. Based on the comic of the same name, it was the story about the latest teenage generation of mutants living at Professor Xavier's School for the Gifted. The film showed the young adults learning to develop their powers and balancing their super-powered responsibilities to a world while trying to carry on a normal life. That may sound like a very familiar premise to modern TV viewers, but at the time Generation X was on the cusp of something revolutionary. Fox just didn't see it coming.
The movie was originally conceived as a television series pilot, but the Fox executives decided not pursue it as a series. The pilot was salvaged into a TV film. It was a cautious move that failed to foresee a burgeoning TV trend that was right around the corner. Very soon after this, TV networks would be loading up on series surrounding teenagers and young adults with unusual abilities; like Buffy The Vampire Slayer, Roswell, Charmed, and Smallville to name a few. Many more successful series aimed at the burgeoning young adult sci-fi market would come over the years, including X-Men related series like The Gifted.
If Fox gave Generation X the support it would have received as an ongoing new series, more promotion and time to develop a following, the series could have rode the same wave of teen sci-fi enthusiasm that carried similar shows for long runs.