My main criteria for inclusion is a) more than one LP release and b) a pedal steel guitarist in the band. Gene Clark is an exception, since he's not a "band." The Byrds technically only did one album of country-rock, so they are not included. The Allmans, Charlie Daniels, Eagles, Dirt Band, Pure Prairie League etc. are not considered since they had no steel player. (Plus, I don't think of any of them as "country-rock" but more "Southern Rock" or "Bluegrass Rock" or "Soft Rock" depending on the band).
I don't know how you'd define Commander Cody, but they did rock out, so I put them on rather than leave them off. And I think Buck and the Buckaroos really helped laid the ground for the country-rock movement.....so I added them, too.
Just trying to keep the list reasonable......