Two important collections of cemetery records are:
Brinley, Lorine. Cemetery Records: A Texas and Louisiana Collection. Salt Lake City, Utah: Genealogical Society, 1959. (Family History Library book 976 A1 no. 3; film 908964 Item 8.) This contains card indexes.Transcripts for many cemetery are on films 206289-303.
Cemetery Records of Texas. Six Volumes. Salt Lake City, Utah: Genealogical Society, 1956-63. (Family History Library book 976.4 V3d; films 897234-35.)
Lists of the cemeteries in each county that are included in the above collections are in Sharry Crofford-Gould, Texas Cemetery Inscriptions: A Source Index. San Antonio, Texas: Limited Editions, 1977. (Family History Library book 976.4 A1 no. 56.)
Some of the earliest burials in Texas are recorded in Mrs. Malcolm B. Biggerstaff, Four Thousand Tombstone Inscriptions from Texas, 1745-1870: Along the Old San Antonio Road and the Trail of Austin's Colonists. Oklahoma City: Oklahoma Historical Society, 1952. (Family History Library book 976.4 V3b.)
The Daughters of the American Revolution (DAR) collection also contains tombstone inscriptions from many Texas cemeteries. This collection is described in the "Genealogy" article in this Wiki.