| 301 | STS Petroleum LLC | Houston, TX 77289 | Oil & Gas Operator | May 2025 |
| 302 | Sue-Ann Operating, L.C. | Victoria, TX 77903 | Oil & Gas Operator | May 2025 |
| 303 | Suemaur Expl. & Prod., LLC | Corpus Chrsti, TX 78401 | Oil & Gas Operator | Jun 2024 |
| 304 | Tema Oil And Gas Company | Houston, TX 77084 | Oil & Gas Operator | May 2025 |
| 305 | Tepco Resources, Inc. | Houston, TX 77027 | Oil & Gas Operator | Sep 2004 |
| 306 | Tepco, Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 1999 |
| 307 | Texaco E & P Inc | Houston, TX 77099 | Oil & Gas Operator | May 2025 |
| 308 | Texas Fuel Company | Galveston, TX 77550 | Oil & Gas Operator | May 2025 |
| 309 | Texas Independent Explor LTD. | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 310 | Texas Independent Explor., Inc. | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 311 | Texas Meridian Res. Expl., Inc. | Houston, TX 77079 | Oil & Gas Operator | Jun 1998 |
| 312 | Texas, Les & Co. | Austin, TX 78746 | Oil & Gas Operator | May 2025 |
| 313 | Texcal Energy (GP) LLC | Denver, CO 80202 | Oil & Gas Operator | Mar 2016 |
| 314 | Torrent Oil LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 315 | Transatlantic Petr (USA) Corp. | Dallas, TX 75206 | Oil & Gas Operator | May 2025 |
| 316 | Transtexas Gas Corporation | Houston, TX 77265 | Oil & Gas Operator | Aug 2005 |
| 317 | Travis Operating, LLC | Kingwood, TX 77345 | Oil & Gas Operator | May 2025 |
| 318 | Tri-Union Development Corp. | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 319 | Tristar Exploration, Inc | Pflugerville, TX 78660 | Oil & Gas Operator | May 2025 |
| 320 | Truth Resources LP | Houston, TX 77090 | Oil Operator | Sep 2021 |
| 321 | Union Oil Co Of California | Midland, TX 79706 | Oil & Gas Operator | Jan 2022 |
| 322 | Union Seaboard Corporation | Houston, TX 77024 | Oil & Gas Operator | Mar 2008 |
| 323 | Vast Oil TX Operating LLC | Fullerton, CA 92832 | Oil & Gas Operator | May 2025 |
| 324 | Venoco, Inc. | Houston, TX 77002 | Oil & Gas Operator | Mar 2008 |
| 325 | Ventum Oil And Gas, LP | Northbrook, IL 60062 | Oil & Gas Operator | Mar 2010 |
| 326 | Viking Resources, Inc. | Stafford, TX 77477 | Oil & Gas Operator | May 2025 |
| 327 | Vintage Petroleum, Inc. | Houston, TX 77046 | Oil & Gas Operator | Jan 2025 |
| 328 | Wacker Oil Inc | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 329 | Wagner Oil Company | Fort Worth, TX 76102 | Oil & Gas Operator | May 2025 |
| 330 | Wagner, Duer & Co. | Fort Worth, TX 76102 | Oil & Gas Operator | Jan 1999 |
| 331 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 332 | Walter Oil & Gas Corporation | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 333 | Weber Energy Corporation | Dallas, TX 75219 | Oil & Gas Operator | Feb 2017 |
| 334 | White Oak Operating Company LLC | Houston, TX 77077 | Oil & Gas Operator | May 2025 |
| 335 | Whittington Operating Company | Houston, TX 77069 | Oil & Gas Operator | May 2025 |
| 336 | Womack Operating, LLC. | Houston, TX 77057 | Oil & Gas Operator | May 2025 |
| 337 | Wood Energy Corporation | Baytown, TX 77520 | Oil & Gas Operator | Jun 1999 |
| 338 | XTO Energy Inc. | Spring, TX 77389 | Oil & Gas Operator | May 2025 |
| 339 | Yordes Energy, LLC | El Campo, TX 77437 | Oil Operator | May 2025 |
| 340 | York E & P, LLC | Boling, TX 77420 | Oil & Gas Operator | May 2025 |