I don't believe the gray rat snake's range extends far enough south for you to run into any of them. Most of the various varieties of rat snakes seem to have exclusive ranges with some overlap where the ranges meet. Your area would likely have the yellow rat snake than any other form.
And yeah, black racers seem to be abundant just about everywhere. If you ever see a black snake that is heavy bodied with more of a shiny blue-black appearance, that would be the eastern indigo snake. But they are getting rare to find, and protected all along their range. The indigo will tackle and eat venomous snakes, so they would be good to have around and encourage to hang out nearby.
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