I will reiterate what the others have said about Mtn Kings, Gray-banded Kings, Mexican (Variable, San Luis Potosi) Kings, and Milksnakes. They are pretty, but can sometimes be a little harder to start. A captive bred gray-band that is well started on unscented pinkies isn't a bad choice, but the common kings are better.
Of course, some common kingsnakes (and even cornsnakes) can be tough until they are securely started on pinkie mice. This is where you have to find a breeder you trust.
As for the common kingsnakes, I would make these comments -
Mexican Black Kingsnake - cheap, reasonable size, docile, good feeders
California Kingsnake - cheap, reasonable size, some are a bit nippy, variety of morphs
Desert Kingsnake - harder to find, reasonable size, docile, good feeders
Speckled Kingsnake - harder to find, reasonable size, somewhat high strung
Eastern Kingsnake - big, rat eating machines. Can get large (6ft) and therefore cost more to house/feed, not easy to find cb babies
Florida Kingsnake - cheap, common, hardy, easy to feed, can get up to 6 feet so more expensive to house and feed
Blotched/Appalachicola Kingsnake - common, attractive, similar in size to the last two ssp.
Eastern Black Kingsnake - uncommon in hobby, some are high strung
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Chris Harrison
Central Texas