Well, there is the Mojang Cloak, which is staff only. Holiday Cloaks, which can only been worn during halloween and christmas, And the 1milth buyer cloak. There was the bacon cloak which was given to the guy who invented pigmen, but he got it taken away cause people spam asked for cloaks. Sad story it is. But these are so far all the cloaks. Maybe released in an official update? Who Knows.