I want to add in that a good thing to know if you might get a potential Legendary from a hoard is your pets color. Since as we know that pets can only bring back things of their color and the like. So if you are looking for a certain legendary well you have a pet of that particular color and then potential for them to bring it back.

From what I saw on the amazing Pet Color Compedium there's quite a few choices for things like getting a particular pet. I know I'm going to be on the lookout for pets in certain colors so I can try for the other legendaries (I needs my Noodle dragon! Noo-long looks so adorable <3)