The database America's News from Newsbank offers coverage of the Amarillo Globle-News from 2002 to the present and coverage of almost 100 other Texas newspapers from sometimes as far back as 1985.
The Library of Congress site Chronicling America: Historic American Newspapers includes coverage of The Amarillo Daily News from 1911 through 1922 and the Canyon City News / Randall County News from 1903 to 1909, as well as Amarillo's Daily Panhandle from 1907 to 1920 and a few years of the Canyon City Stayer, the Amarillo Weekly Herald, and the Amarillo Twice-a-Week Herald.
The website The Portal to Texas History, from the University of North Texas, includes newspaper coverage for Hemphill County, Borger, Canadian, Claude, Hereford, Panhandle, and Amarillo.