There was an adorable one in the kids' division at Ad Astra this weekend. It was introduced as a young wizard looking for her runaway pet dragon. Little girl in robes and a pointy sparkly hat comes out on stage dragging a teddy bear that's larger than herself, calling "Fluffy! Where are you, Fluffy? I have Mr. Cuddles!" Then a guy offstage answers her with a RAAAAAWWRRRRR! and she looks in that direction and goes "There you are! Come on, Fluffy, let's go home."
I think the guy playing Fluffy might have been her dad.
But if he hadn't been available on the day she could equally have used a recorded roar (either his, which was awesome, or some downloaded sound file).