The popularity of The CW's Supernatural has resulted in several attempts at a spinoff series. Since its 2005 release, Supernatural ran for a total of 15 seasons, covering the exploits of the Winchester brothers as they traveled across America, hunting monsters on the trail of their estranged father. While the main series centered on Sam and Dean and later, the show's resident fallen angel, Castiel the wider world of Supernatural offers rich material to expand on. Other fantasy series, such as The Originals and Chris Carter's Millennium, have proved that spinoffs can be as successful as their flagship shows.

Unfortunately, in Supernatural's case, many of its attempted spinoffs were ill-fated. The absence of the series' beloved main duo was felt in shows like The Winchesters, which focused on Sam and Dean's parents. Earlier spinoffs which were introduced through backdoor pilots were never picked up by the network. Following Supernatural's...