| 1 | Talisman Energy USA Inc. | The Woodlands, TX 77381 | Oil & Gas Operator | May 2016 |
| 2 | Talon Development Company | Boerne, TX 78006 | Oil & Gas Operator | Sep 2007 |
| 3 | Targa Midstream Services LLC | Houston, TX 77002 | Oil Operator | Mar 2023 |
| 4 | TBM Catarina, LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Oct 2025 |
| 5 | Teal Operating, LLC | Dallas, TX 75225 | Oil & Gas Operator | Oct 2021 |
| 6 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 7 | Texakoma Oil & Gas Corp | Dallas, TX 75240 | Oil & Gas Operator | Sep 2014 |
| 8 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | Oct 2025 |
| 9 | Texas Crude Energy, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 2012 |
| 10 | Texas Western Energy Corporation | Portland, TX 78374 | Oil & Gas Operator | Nov 2002 |
| 11 | Texoma Oil Tools, Inc. | Wichita Falls, TX 76308 | Oil & Gas Operator | Oct 2025 |
| 12 | Texron Operating, LLC | Bulverde, TX 78163 | Oil & Gas Operator | Oct 2025 |
| 13 | Texstar North America, Inc. | Waynesboro, MS 39367 | Oil & Gas Operator | Aug 1994 |
| 14 | The Quintin Little Company Inc | Ardmore, OK 73401 | Oil & Gas Operator | Jul 2025 |
| 15 | Thompson, Richard W. Inc. | Plano, TX 75024 | Oil & Gas Operator | Oct 2025 |
| 16 | Three J Energy, Inc. | Seguin, TX 78155 | Oil & Gas Operator | Oct 2025 |
| 17 | Thunder Oil & Gas, LLC | Ardmore, OK 73402 | Oil & Gas Operator | Jun 2025 |
| 18 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | Oct 2025 |
| 19 | Tidewater Minerals Corporation | Orange Grove, TX 78372 | Oil & Gas Operator | Oct 2025 |
| 20 | Tiza Operating Company | Austin, TX 78716 | Oil & Gas Operator | Jan 2000 |
| 21 | Tradestar Energy, Inc. | Hot Springs, AR 71913 | Oil Operator | Feb 2021 |
| 22 | Trans Texas Minerals Company | Austin, TX 78714 | Oil & Gas Operator | Aug 1999 |
| 23 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 24 | Traton Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Mar 2019 |
| 25 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | Oct 2025 |
| 26 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 27 | Trinity Operating (Usg), LLC | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 28 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 29 | Triple "S" Resources Inc | Sapulpa, OK 74066 | Oil & Gas Operator | Jun 1995 |
| 30 | Triple J Investments Inc | Longview, TX 75606 | Oil & Gas Operator | Feb 2023 |
| 31 | Tsoco | Tuleta, TX 78162 | Oil & Gas Operator | Apr 2017 |
| 32 | Turner, M. O. | San Antonio, TX 78278 | Oil & Gas Operator | Apr 2003 |
| 33 | Tuskar (Texas), Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Jan 2016 |