| 1 | T & T Production Co. | Victoria, TX 77902 | Oil & Gas Operator | Feb 1995 |
| 2 | T - C Oil Company | Refugio, TX 78377 | Oil & Gas Operator | Jan 2012 |
| 3 | T-C Oil Company, LLC | Refugio, TX 78377 | Oil & Gas Operator | Oct 2025 |
| 4 | Talon Development Company | Boerne, TX 78006 | Oil & Gas Operator | Sep 2007 |
| 5 | Taos Resources Operating Co LLC | Houston, TX 77037 | Oil & Gas Operator | Dec 2019 |
| 6 | TBC Petroleum | Cuero, TX 77954 | Oil & Gas Operator | Sep 2023 |
| 7 | Team Operating, L.L.C. | Pinehurst, TX 77362 | Oil & Gas Operator | Oct 2025 |
| 8 | Tejas Operating LLC | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 9 | Tepee Petroleum Company, Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2014 |
| 10 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | Oct 2025 |
| 11 | Texas Fuel Company | Galveston, TX 77550 | Oil & Gas Operator | Oct 2025 |
| 12 | Texcal Energy (GP) LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2016 |
| 13 | Texlan Oil Company, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Nov 1994 |
| 14 | Texstar North America, Inc. | Waynesboro, MS 39367 | Oil & Gas Operator | Aug 1994 |
| 15 | Three Mile Joint Venture | Houston, TX 77027 | Oil & Gas Operator | Jul 1995 |
| 16 | Thunderbird Energy, Inc. | Norman, OK 73069 | Oil & Gas Operator | Oct 2025 |
| 17 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | Oct 2025 |
| 18 | Tide Energy, Inc. | Dallas, TX 75206 | Gas Operator | Oct 1994 |
| 19 | Tidemark Petroleum, Inc. | San Antonio, TX 78209 | Oil & Gas Operator | Jul 2002 |
| 20 | Tiger Resources, L.L.C. | Houston, TX 77070 | Oil & Gas Operator | Feb 2004 |
| 21 | Titan Resources I, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jun 2000 |
| 22 | Top Op, L.L.C. | Houston, TX 77077 | Oil & Gas Operator | May 2020 |
| 23 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 24 | Trans-Pecos Resources, Inc. | Houston, TX 77056 | Oil & Gas Operator | Oct 2025 |
| 25 | Transtexas Gas Corporation | Houston, TX 77265 | Oil & Gas Operator | Aug 2005 |
| 26 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 27 | Tri-C Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | Oct 2025 |
| 28 | Tri-Union Development Corp. | Houston, TX 77002 | Oil & Gas Operator | Oct 2025 |
| 29 | Triad Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Oct 2011 |
| 30 | Triangle Three Resources L.L.C. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2024 |
| 31 | Trident Corporation | Woodsboro, TX 78393 | Oil & Gas Operator | Oct 2025 |
| 32 | Trinity Resources, Inc. | Houston, TX 77277 | Oil & Gas Operator | May 2020 |
| 33 | Triple L Oil Company | Corpus Chrsti, TX 78469 | Oil & Gas Operator | Jan 1998 |
| 34 | Triton Oil & Gas Corp. | Houston, TX 77002 | Oil & Gas Operator | Nov 2014 |
| 35 | Tschoepe, Arthur J. | Leakey, TX 78873 | Oil & Gas Operator | Jun 2001 |
| 36 | TT Operating, LLC | Kilgore, TX 75663 | Oil & Gas Operator | Oct 2025 |
| 37 | Tucker Operating Co., Inc. | Victoria, TX 77903 | Oil & Gas Operator | Oct 2025 |
| 38 | TX Petroleum Company | Corpus Chrsti, TX 78412 | Oil & Gas Operator | Apr 1996 |