The release of "Allegiant" signals the inevitable end of the "Divergent" franchise (one final installment, "Ascendant," comes out next year). So it's time to examine what as-yet-unmade young adult novels have a chance to join "Harry Potter" and "The Hunger Games" on the list of Best YA Films.

Although "Divergent" and "Maze Runner" have been commercially-successful dystopian stories, and realistic contemporary tales like "The Fault in Our Stars" have generated critical appeal, many more young adult adaptations have failed to launch -- even ones with built-in fandoms at the ready. Here are 12 optioned YA novels worthy of the big screen.ya books that would make great movies