Well, if you just want what traits are in trade names, the site I previously listed works fine, or the site that Susan linked.
http://iansvivarium.com/cornsnakemorphs.php, cornsnakemorphgallery.com no chart needed.
If you want to know what snake A x snake B = what morph? you will have to use the cornsnake calculator, and get an understanding for genetics.
Example:
The trade name "Butter". Looking on the first site I listed we find that "Butter" is made up of "amel" and "caramel."
However, if you pair together an amel snake, and a caramel snake, you will get 100% normal colored cornsnakes, unless there are hets involved. This is why an understanding of genetics is also needed.
To get butter, one can pair up...
butter x butter
butter x caramel het amel
butter x amel het caramel
amel het caramel x amel het caramel
normal het amel, caramel x butter
normal het amel, caramel x normal het amel, caramel
etc...etc...etc...
So it's not quite as easy as making that into a chart, which is why the cornsnake calc is used.
A good rule of thumb for
most traits: if you want a specific trait to show up in the offspring, then BOTH the mother and father of the offspring must also have that trait, either in homozygous recessive form (i.e. expressing the trait), or in heterozygous form (i.e having one recessive copy for the trait, not expressing the trait)