Oh, yes! There is a wild population around the outskirts of Goldenrod. I think it is a small one - or they all simply spend their time disguised as other Pokemon. But I understand that only a pairing of two Ditto can produce more Ditto children, so I would not be surprised if they are rare.

[The use of them by Breeders is. Kinda creepy for him? But he certainly knows it happens.]

I met Jam when they approached my Pokemon to play.