I recommend this site or the Corn Snake Morph Guide
http://iansvivarium.com/morphs/species/elaphe_guttata/
There are probably other sites but one good one is Ian's Vivarium
http://iansvivarium.com/morphs/species/elaphe_guttata/
The site does not have all the possible combinations. It does have 247 and growing.
Another good resource is the book Cornsnake Morph Guide by Charles Pritzel. He made yearly editions through 2011.