Roky & the 13th Floor Elevators from Austin - 1966 (note the "electric jug" - the most unique instrument in rock history):
https://www.youtube.com/watch?v=gHK9vj0VE7w
Zakary Thaks from Corpus Christi - 1965:
https://www.youtube.com/watch?v=nLWfQRNOCvc
Rusty Wier and The Wig from Austin - 1965:
https://www.youtube.com/watch?v=T-Tes9UhWl0
Shiva's Headband - Austin 1967;
https://www.youtube.com/watch?v=vPX5VutxhEg
Sir Douglas Quintet - San Antonio 1965:
https://www.youtube.com/watch?v=XboE3_7KZ3Y
Even earlier Texas rock - Buddy Holly - Lubbock, Texas 1957:
https://www.youtube.com/watch?v=Rk6YDzmqZ0I
https://www.youtube.com/watch?v=XEl3UUl1Fmw
Buddy Holly is often regarded as the artist who defined the traditional rock-and-roll lineup of two guitars, bass, and drums.