Bakugan (cancelled live-action film adaptation of toy line; 2010s)
Bakugan is a toy series released by Sega Toys and Spin Master in 2006. The success of the toys spawned a few anime series by the same name from 2007 to 2012. In 2010, a live-action film was announced by Warner Bros. Harald Zwart, director of the Karate Kid remake, is allegedly the director.
No further updates have been released since the 2010 announcement. Zwart's IMDb page doesn't even mention the film (as of April 2016) and a release date has not been announced. As such, it's unknown whether or not the film will be released anytime soon or if the film has been quietly cancelled.