9. Tool - Title Unknown
It's been seven long years since Tool last released a studio album, and the group's hardcore fans are getting pretty antsy. Brief tours in 2009 and 2012 did much to appease them but, by this point, they won't be satisfied with anything besides a new album. The prog-metal quartet swear they've been chipping away at songs since 2009 and they hope to finally release them this year, but we'll believe it when we see it. This is a group that works very slowly. They've been around 23 years and only have four albums to show for it.