I would have to say that there are a few that come to mind.
1. Black king snake - Very hardy snake that is IMHO very attractive
2. Prairie king snake - same reasons.
3. Great plains rat snake - Same.
4. Kisatchie/Slowinskii corn - Same.
Im a little biased towards the native snakes though!! 
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RATS
1.0 Corn snake "Warpath" (KY locale)
1.0 Black rat snake "Havok" (KY locale)
1.1 Black rat snakes "Reaper and Mystique" (MO locale)
1.0 Albino Black rat snake "Malakai" (Dwight Good stock)
1.0 Everglades rat snake "Deadpool" (Dwight Good stock)
0.1 Greenish rat snake "Rogue" (Dwight Good stock)
1.0 Yellow rat snake "Wolverine" (Dwight Good stock)
1.0 Grey rat snake "Punisher" (White oak phase)(Dwight Good stock)
RACERS
1.0 Eastern Yellow Belly racer "Nightcrawler" (MO locale)
KINGS
1.1 California king snake "Bandit and Moonstar" (Coastal phase)
1.0 Prairie king snake "Bishop" (KY locale)
0.1 Black king snake "Domino" (KY locale)
1.0 Desert Kingsnake "Gambit"
0.1 Florida Kingsnake
MILKS
0.0.1 Eastern Milk snake "Cable" (KY locale)
0.0.1 Eastern/Red milk intergrade "Omega Red" (KY locale)
BULLS/GOPHERS/PINES
0.1 Sonoran Gopher
Good luck and Happy Herping
Brian