Old school outlaw country music?

i just recently started listening to country music but the only kind i really like is the old school Texas outlaw kind such as David Allen Coe, Merle Haggard, Johnny Cash, George Jones, Waylon Jennings. i was just wondering what other good artist are out there that are similar to them. and if there are any truly good modern country artist, i do like one called big & rich tho.