Not sure if anyone else has said anything about it, but most New World (mainly North American) rat snakes are no longer in the Genus Elaphe even though many breeders still think they are. They are in the Genus Pantherophis as they were found not to be as closely related to old world rat snakes as we first thought.
Black rat snake aka Eastern rat snake: Pantherophis alleghaniensis
Gray rat snake: Pantherophis spiloides
Yellow rat snake: Pantherophis alleghaniensis (quadrivittata is rarely used now due to it just being a color/pattern variation of the Eastern rat snake)
Everglade ratsnake: Pantherophis alleghaniensis (rossalleni rarely used on as well because also Eastern rat snake)
Baird’s ratsnake: Pantherophis bairdi
Emory ratsnake AKA Great Plains ratsnake: Pantherophis emoryi
Texas ratsnake: Pantherophis obsoleta lindheimeri
Greenish rat snake (mix between black ratsnake and yellow ratsnake locals): Pantherophis alleghaniensis
Fox snake: Pantherophis vulpinus
Corn snake: Pantherophis guttatus
Western Green rat snake: Senticolis triaspis
That is all I can remember for now, but there are of course more. If you need me to look into more of the New world rats I would be glad to.