Some extinct creatures I would like to see brought back are the "relatives" of human beings so we can easily and closely study our evolutinary history.
As for a mythical creature: the Chopalope, a rabbit with antlers.
Definitely a Griffin! I just think they are so bad *** I would love to have one. Dragons are nice but I don't think I can keep one hidden for very long xD
A mythical creature I would love to see return is the cyclops. I've always had an admiration for the creatures and I'm sure my numerous hours playing the Yu-Gi-Oh! card game have only led to a deeper fascination with them. Not only are they absolutely colossal and able to exert brute force but there single eye is extremely intimidating. As they say, however, the bigger they are, the harder they fall and without its eye, a cyclops is useless as the segment of Homer's Odyssey involving Polyphemus serves to illustrate.