Perry's Index to the Aesopica
Perry reserves 457 for a joke about a boy on a runaway horse. "Someone
saw him and asked him where he was going. The boy pointed to the horse
and said, 'Wherever he likes!'" (told by Lucian in his Cynicus
You can find a compilation of Perry's index to the Aesopica in the gigantic appendix to his
edition of Babrius and Phaedrus for the Loeb Classical Library
(Harvard University Press: Cambridge, 1965). This book is an absolute must for anyone interested
in the Aesopic fable tradition. Invaluable.