Photos of the cases were recently shared by Twitter account @TommyBo50387266. The colors are Cantaloupe, Pistachio, Capri Blue, and Amethyst. These would be in addition to the eight colors already offered.
It's unclear if these are legit cases but the timing is correct. Apple appears to be readying a special event on April 20th and the new cases would likely become available some time after that.
Check out the photos below and please download the iClarified app or follow iClarified on Twitter, Facebook, YouTube, and RSS for updates.