| 401 | Striper Oil, Inc. | Dallas, TX 75379 | Oil & Gas Operator | Apr 2002 |
| 402 | Sundown Energy LP | Dallas, TX 75248 | Oil & Gas Operator | May 2025 |
| 403 | SWN Production LLC | Spring, TX 77389-4954 | Oil & Gas Operator | Feb 2022 |
| 404 | Talaria Oil & Gas LLC | Denver, CO 80203 | Oil Operator | May 2025 |
| 405 | Tamarack Petroleum Company, Inc. | Midland, TX 79701 | Oil & Gas Operator | May 2025 |
| 406 | Tana Oil And Gas Corporation | Irving, TX 75062 | Oil & Gas Operator | Mar 2000 |
| 407 | TC Oil And Gas, LLC | Denton, TX 76205 | Oil Operator | May 2025 |
| 408 | TD Natural Resources LLC | Cuero, TX 77954 | Oil & Gas Operator | May 2025 |
| 409 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | May 2025 |
| 410 | Tech Resources, Inc. | Georgetown, TX 78628 | Oil & Gas Operator | Dec 2001 |
| 411 | Tejones Operating Corporation | San Antonio, TX 78217 | Oil & Gas Operator | May 2025 |
| 412 | Tenex Corporation | Houston, TX 77227 | Oil & Gas Operator | Dec 2007 |
| 413 | Tenison Oil Company | Abilene, TX 79605 | Oil & Gas Operator | May 2025 |
| 414 | Texakoma Oil & Gas Corp | Dallas, TX 75240 | Oil & Gas Operator | Sep 2014 |
| 415 | Texas American Resources Company | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 416 | Texas Consolidated Pet. Corp. | Fort Worth, TX 76109 | Oil & Gas Operator | May 2025 |
| 417 | Texas Energy Reserves, Inc | New Braunfels, TX 78130 | Oil & Gas Operator | Jun 1996 |
| 418 | Texas International Oper., LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Dec 2013 |
| 419 | Texcal Oil Co | Cuero, TX 77954 | Oil & Gas Operator | Feb 2006 |
| 420 | Texlan Oil Company, Inc. | Tyler, TX 75701 | Oil & Gas Operator | Nov 1994 |
| 421 | Texstar North America, Inc. | Waynesboro, MS 39367 | Oil & Gas Operator | Aug 1994 |
| 422 | Thomas, Mike | Nixon, TX 78140 | Oil Operator | May 2025 |
| 423 | Three J Energy, Inc. | Seguin, TX 78155 | Oil & Gas Operator | May 2025 |
| 424 | Tidal Petroleum, Inc. | Schertz, TX 78154 | Oil & Gas Operator | May 2025 |
| 425 | Tipperary Oil & Gas Corp | Denver, CO 80202 | Oil & Gas Operator | May 2014 |
| 426 | Tiza Energy, Inc. | Austin, TX 78715 | Oil & Gas Operator | May 2025 |
| 427 | Tiza Operating Company | Austin, TX 78716 | Oil & Gas Operator | Jan 2000 |
| 428 | Top Op, L.L.C. | Houston, TX 77077 | Oil & Gas Operator | May 2020 |
| 429 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 430 | Tower Resources Inc | Conroe, TX 77304 | Oil & Gas Operator | May 2025 |
| 431 | Tracker Oil & Gas, Inc. | Bastrop, TX 78602 | Oil & Gas Operator | May 2025 |
| 432 | Trek Resources, Inc. | Dallas, TX 75207 | Oil & Gas Operator | May 2025 |
| 433 | Tri-C Resources, LLC | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 434 | Tri-County Operating Company | Seguin, TX 78156 | Gas Operator | Feb 1997 |
| 435 | Tsar Energy, LLC | Dallas, TX 75205 | Oil & Gas Operator | May 2025 |
| 436 | Tuleta Energy Partners, LLC | Norman, OK 73072 | Oil & Gas Operator | May 2025 |
| 437 | Tuskar (Texas), Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Jan 2016 |
| 438 | Union Gas Operating Company | Houston, TX 77014 | Oil & Gas Operator | May 2025 |
| 439 | Union Pacific Resources Co. | Fort Worth, TX 76101 | Oil & Gas Operator | Sep 2002 |
| 440 | Unit Petroleum Company | Tulsa, OK 74170 | Oil & Gas Operator | May 2025 |
| 441 | United Oil & Minerals, Inc. | Austin, TX 78746 | Oil & Gas Operator | Jan 2001 |
| 442 | United Operating, LLC *** | Midland, TX 79710 | Oil & Gas Operator | May 2025 |
| 443 | United Resources LP | Austin, TX 78746 | Oil & Gas Operator | Oct 2011 |
| 444 | Verdun Oil & Gas LLC | Houston, TX 77024 | Oil & Gas Operator | May 2025 |
| 445 | Viceroy Petroleum, LP | College Sta, TX 77845 | Oil & Gas Operator | May 2025 |
| 446 | Viola Production Inc | Dallas, TX 75251 | Oil & Gas Operator | May 2025 |
| 447 | Vomela Resources Inc. | Flatonia, TX 78941 | Oil & Gas Operator | May 2025 |
| 448 | W.O.G., Inc. | Midland, TX 79702 | Oil & Gas Operator | Mar 2008 |
| 449 | Wainoco Oil & Gas Company | Houston, TX 77024 | Oil & Gas Operator | Dec 2005 |
| 450 | Warwick-Artemis, LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | May 2025 |
| 451 | Waters Eng. & Operating, Inc. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Sep 2013 |
| 452 | WCS Oil & Gas Corporation | Dallas, TX 75209 | Oil & Gas Operator | Aug 2021 |
| 453 | Weber Energy Corporation | Dallas, TX 75219 | Oil & Gas Operator | Feb 2017 |
| 454 | Western Energy Group, LLC | Leander, TX 78641 | Oil & Gas Operator | May 2025 |
| 455 | Westridge Oil & Gas Properties | Mineral Wells, TX 76068 | Oil & Gas Operator | May 2025 |
| 456 | Weststar Oil & Gas Inc | Edmond, OK 73013 | Oil & Gas Operator | Mar 2025 |
| 457 | Wilbanks, Bruce A. Company | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 458 | Wild Cat Operating Company | Victoria, TX 77903 | Oil & Gas Operator | Mar 2008 |
| 459 | Wilmoth Interests, Inc. | Marion Center, PA 15759 | Oil & Gas Operator | Mar 2025 |
| 460 | Wilson, Billy R. | New Braunfels, TX 78130 | Oil & Gas Operator | May 2025 |
| 461 | Wind River Resources Inc | Tulsa, OK 74136-6381 | Oil & Gas Operator | Jun 2010 |
| 462 | Winn Exploration Co., Inc. | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 463 | Wofford, C. J. | El Campo, TX 77437 | Oil & Gas Operator | May 2025 |
| 464 | WTXR Operating (Texas), Inc. | Carrollton, TX 75007 | Oil Operator | May 2025 |
| 465 | Xeric Oil & Gas Corporation | Midland, TX 79702 | Oil & Gas Operator | Apr 2014 |
| 466 | Xog Operating LLC | Midland, TX 79702 | Oil & Gas Operator | May 2025 |
| 467 | Yates Energy Corporation | Roswell, NM 88202 | Oil & Gas Operator | May 2025 |
| 468 | Zachry Exploration, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | May 2025 |
| 469 | Zachry Exploration, LTD. | San Antonio, TX 78205 | Oil & Gas Operator | Jan 2009 |
| 470 | Zarvona Energy LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 471 | Zaza Energy, LLC | Houston, TX 77010 | Oil & Gas Operator | May 2025 |