Well, I would call this a Texas Trio, but John Hiatt is from Indianapolis, but he sounds Texas enough with the other two guys. While not commercially successful, John Hiatt gained esteem from critics for his songwriting. His songs have been covered by a ton of artists including Willie Nelson, Bob Dylan, Eric Clapton, Iggy Pop and many more. People may know him from his piano song, "Have a Little Faith in Me"
This is the song Perfectly Good Guitar.
Joe Ely is a Texan and again never achieved commercial success, but is well respected within the music community. Him and Bruce Springsteen have shared the stage at several concerts singing Ely's songs.
This is Joe and Bruce singing Ely's "Settle for Love" in concert
Last up is eponymous Texas singer/songwriter Guy Clark with a song called "Parking Lot" I'm sure many people that grew up in the country or the city for that matter, can identify with this song and what happens after the bar closes.
This is from an Austin City Limits episode entitled "Songwriters Showcase" and featured all 3 artists plus Llye Lovett. I think it's a great episode.