| 1 | Tallgrass Energy, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Oct 2025 |
| 2 | Talon Development Company | Boerne, TX 78006 | Oil & Gas Operator | Sep 2007 |
| 3 | TCRG Drilling & Operating, LLC | Fort Worth, TX 76107 | Oil Operator | Oct 2025 |
| 4 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Oct 2025 |
| 5 | Tecpetrol Operating LLC | Houston, TX 77027 | Oil & Gas Operator | Dec 2015 |
| 6 | Tejas Petroleum Resources, LLC | Aubrey, TX 76227 | Oil & Gas Operator | Oct 2025 |
| 7 | Tepee Petroleum Company, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2014 |
| 8 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 9 | Texas Crude, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 1995 |
| 10 | Texas Fuel Company | Galveston, TX 77550 | Oil & Gas Operator | Oct 2025 |
| 11 | Texas Independent Explor LTD. | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 12 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 13 | Texron Operating, LLC | Bulverde, TX 78163 | Oil & Gas Operator | Oct 2025 |
| 14 | Third Coast Energy, Inc. | Corpus Chrsti, TX 78427 | Oil & Gas Operator | Oct 2025 |
| 15 | TNT Petroleum Company, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Feb 1996 |
| 16 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 17 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 18 | Trinity River Energy Oper, LLC | Houston, TX 77008 | Oil & Gas Operator | May 2018 |
| 19 | Tristar Exploration, Inc | Pflugerville, TX 78660 | Oil & Gas Operator | Oct 2025 |