It all depends on how you define "country music"
One of the primary offshoots of country is Tejano music. Same rhythm & country "twang" but sung in a combination of Spanish & English. Doesn't get much play beyond the southwest states, but where it does get played, people like it A LOT. So, from that "country music" there's Selena. Incredibly popular, the Hispanic Shania Twain. RIP
There's also Cowboy Troy (he's black). Again, same rhythm & country "twang" but he also raps. Has more than just a couple of albums and people go crazy over him. He's been on tour with & opened for Big & Rich and you don't get any bigger in country music than those two. So, he would be another star to add to your list.