The ones in bold I've either seen or met and would recommend them.

10 City Run
Aaron Watson
Bart Crow Band
Bleu Edmondson
Brandon Rhyder
Bruce Robinson
Buster Jiggs
Chris Knight
Charlie Robison
Christian Frieson
Corb Lund
Cory Morrow
Cross Canadian Ragweed
Curtis Grimes
The Damphools
Davin James
Dean Seltzer and the Redneck Mothers
Deryl Dodd
Django Walker (son of Jerry Jeff Walker)
Donny Waits
Doug Moreland
Dub Miller
Eleven Hundred Springs
Eli Young Band
Emory Quinn
Hogg Maulies
JJ Henson Band
Jack Ingram
Jackson Taylor
Jamie Richards
Jarrod Birmingham
Jason Allen Band
Jason Boland and the Stragglers
Jesse Brand
Jimmy LaFave
John D. Hale Band
Johnny Cooper
Johnny Solinger
Josh Abbott
Kelly Willis
Kevin Fowler
Kyle Park
Larry Joe Taylor
Micky and the Motorcars
Mark David Manders
Max Stalling
Miranda Lambert
No Justice
Pat Green
Paul Eason
Randy Rogers Band
Ray Wylie Hubbard
Reckless Kelly
Robert Earl Keen
Roger Cowan
Roger Creager
Ryan Bingham
Scooter Brown Band
South First Band
Stan Crawford
Stoney LaRue
Sunny Sweeney
The Britt Lloyd Band
Casey Donahew Band
The Gourds
The Great Devide
The Kyle Bennett Band
The Scott Wiggins Band
Tommy Alverson
Travis Mitchell Band
Two Tons of Steel
Wade Bowen
William Clark Green
Zona Jones