Red Rat's are just another common name for cornsnakes. They are both "one and the same".
Black ratsnakes come in quite a few different morphs. They come in genetic mutations such as......
Black Rat morphs:
amel (i.e. albino)
Cinnamon
Albino Cinnamon
Lemon Cow Sucker
albino Lemon Cow Sucker
Albino "Rusty"
Brindle
Calico
leucistic
White-sided
axanthic
hypoxanthic (extremely reduced yellow pigment except for a few random colored scales here and there)
Lavender
Hypomelanistic
Texas Ratsnake morphs:
albino
axanthic
hypomelanistic
leucistic
white-sided
There are several other North American ratsnakes that come in similar morphs too, as well as other species like Asian/European rats, etc..
~Doug
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"a snake in the grass is a GOOD thing" 
