| 1 | T.O.I. | Midland, TX 79710 | Oil & Gas Operator | Mar 2001 |
| 2 | Tag Operating Company, Inc. | Houston, TX 77092 | Oil & Gas Operator | Oct 2025 |
| 3 | Tallgrass Energy, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Oct 2025 |
| 4 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | Oct 2025 |
| 5 | Teco Operating Company | Athens, TX 75751 | Oil & Gas Operator | Jun 2001 |
| 6 | Tema Oil And Gas Company | Houston, TX 77084 | Oil & Gas Operator | Oct 2025 |
| 7 | Tema Oil And Gas, LLC | Houston, TX 77040 | Oil & Gas Operator | Apr 2000 |
| 8 | Tepee Petroleum Company, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2014 |
| 9 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 10 | Texas Crude Energy, Inc. | Houston, TX 77256 | Oil & Gas Operator | Oct 2012 |
| 11 | Texas Energy & Environmental Inc | Houston, TX 77269 | Oil & Gas Operator | Oct 1998 |
| 12 | Texas Independent Explor LTD. | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 13 | Texas Petroleum Investment Company | Houston, TX 77057 | Oil & Gas Operator | Oct 2025 |
| 14 | Texas Southern Petroleum Corp. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Oct 2025 |
| 15 | Texron Operating, LLC | Bulverde, TX 78163 | Oil & Gas Operator | Oct 2025 |
| 16 | TGX Corporation | Houston, TX 77002 | Oil & Gas Operator | Sep 2004 |
| 17 | Three C Exploration, LLC | Hebbronville, TX 78361 | Oil & Gas Operator | Oct 2025 |
| 18 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | Oct 2025 |
| 19 | Tierra Mineral Development, L.C. | Dallas, TX 75244 | Oil & Gas Operator | Oct 1994 |
| 20 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 21 | TR Offshore, LLC | Corpus Chrsti, TX 78413 | Oil & Gas Operator | Oct 2025 |
| 22 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 23 | Traton Operating Company | Kingwood, TX 77339 | Oil & Gas Operator | Mar 2019 |
| 24 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 25 | Triple L Oil Company | Corpus Chrsti, TX 78469 | Oil & Gas Operator | Jan 1998 |
| 26 | Tschoepe, Arthur J. | Leakey, TX 78873 | Oil & Gas Operator | Jun 2001 |
| 27 | Tucker Operating Co., Inc. | Victoria, TX 77903 | Oil & Gas Operator | Oct 2025 |
| 28 | Tuthill & Barbee | Amarillo, TX 79101 | Oil & Gas Operator | Nov 1994 |
| 29 | TX Petroleum Company | Corpus Chrsti, TX 78412 | Oil & Gas Operator | Apr 1996 |
| 30 | Txco Resources Inc. | San Antonio, TX 78280 | Oil & Gas Operator | Oct 2025 |
| 31 | Txla Energy, Inc. | Houston, TX 77018 | Oil & Gas Operator | Oct 2025 |