| 301 | Haber Resources Corporation | Houston, TX 77063 | Oil & Gas Operator | Mar 1999 |
| 302 | Halbouty, Michel T. | Houston, TX 77056 | Oil & Gas Operator | Aug 1997 |
| 303 | Halcon Resources Operating, Inc. | Tulsa, OK 74135 | Oil & Gas Operator | Dec 2013 |
| 304 | Hall-Houston Oil Company | Houston, TX 77002 | Oil & Gas Operator | Oct 2002 |
| 305 | Hamill Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Apr 1999 |
| 306 | Hamill, Claud B. Estate Of | Houston, TX 77002 | Oil & Gas Operator | Nov 1995 |
| 307 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | May 2025 |
| 308 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 309 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 310 | Hardwick Oil Company | Sugar Land, TX 77478 | Oil & Gas Operator | Nov 2014 |
| 311 | Harrison, Sam G. Oil, Inc. | Houston, TX 77019 | Oil & Gas Operator | Nov 2019 |
| 312 | Harvest Petroleum Inc. | Frisco, TX 75033 | Oil & Gas Operator | May 2025 |
| 313 | Hawthorne Oil And Gas Corp. | Houston, TX 77227 | Oil & Gas Operator | Sep 1993 |
| 314 | Headington Oil Company, L.P. | Dallas, TX 75231 | Oil & Gas Operator | Mar 2008 |
| 315 | Headline Resources, Inc. | Richardson, TX 75080 | Oil & Gas Operator | Aug 1997 |
| 316 | Hennig Production Co., Inc. | Tyler, TX 75701 | Oil & Gas Operator | May 2025 |
| 317 | Hewitt, Robert J. | Victoria, TX 77901 | Oil & Gas Operator | Jun 2004 |
| 318 | Hgi Corporation | Nada, TX 77460 | Oil & Gas Operator | Apr 2016 |
| 319 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | May 2025 |
| 320 | Hollimon Oil Corporation | Castroville, TX 78009 | Oil & Gas Operator | Nov 2016 |
| 321 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | May 2025 |
| 322 | Horizon Exploration Company | Houston, TX 77019 | Oil & Gas Operator | Aug 2002 |
| 323 | Houston Expl. & Prod. Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Aug 2003 |
| 324 | Houston Exploration Co, The | Houston, TX 77002 | Oil & Gas Operator | Apr 2017 |
| 325 | Houston Gulf Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | May 2025 |
| 326 | Houston Hydrocarbons, Inc. (A) | Houston, TX 77042 | Oil & Gas Operator | Sep 2004 |
| 327 | Houston Oil & Gas Company, Inc. | Houston, TX 77063 | Oil & Gas Operator | Aug 1995 |
| 328 | Houston Operating, Inc. | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 329 | Houston Petroleum Company | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 330 | Houston Resources Corp. | Houston, TX 77002 | Oil & Gas Operator | Apr 2003 |
| 331 | Howard Exploration, Inc. | Houston, TX 77069 | Oil & Gas Operator | May 2025 |
| 332 | Howell Petroleum Corporation | Houston, TX 77251 | Oil & Gas Operator | Oct 2015 |
| 333 | HRB Operating Company, Inc. | Bridgeport, TX 76426 | Oil & Gas Operator | May 2025 |
| 334 | Hughes, Dan A. Company | Beeville, TX 78104 | Oil & Gas Operator | May 2006 |
| 335 | Hughes, Dan A. Company, L.P. | Beeville, TX 78104 | Oil & Gas Operator | May 2025 |
| 336 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | May 2025 |
| 337 | Hunt Petroleum Corporation | Dallas, TX 75201 | Oil & Gas Operator | Nov 2008 |
| 338 | Huntington Energy LLC | Nichols Hill, OK 73116 | Oil & Gas Operator | May 2025 |
| 339 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 340 | Hurricane Oil And Gas Co., Inc. | Houston, TX 77057 | Oil & Gas Operator | Mar 2008 |
| 341 | Hyquest Energy, Inc. | Midland, TX 79710 | Oil & Gas Operator | Mar 2015 |
| 342 | Indexgeo & Associates, Inc. | Houston, TX 77002 | Oil & Gas Operator | Apr 2009 |
| 343 | Inland Ocean, Inc. | San Antonio, TX 78205 | Oil & Gas Operator | May 2025 |
| 344 | Ip Petroleum Company, Inc. | Houston, TX 77210 | Oil & Gas Operator | Mar 2008 |
| 345 | Ipact | Austin, TX 78734 | Oil & Gas Operator | May 2025 |
| 346 | Iwr Operating, LLC | Dallas, TX 75248 | Oil Operator | May 2025 |
| 347 | J-W Operating Company | Christoval, TX 76935 | Oil & Gas Operator | May 2025 |
| 348 | J2R Energy, LLC | Houston, TX 77084 | Oil Operator | May 2025 |
| 349 | Jamex II LTD., L.L.P. | Dallas, TX 75252 | Oil & Gas Operator | Sep 2002 |
| 350 | Jamex, Inc. | Lewisville, TX 75067 | Oil & Gas Operator | May 2025 |
| 351 | Janex Oil Co., Inc. | Dallas, TX 75219 | Oil & Gas Operator | Jun 2005 |
| 352 | Jet Oil Producers, Inc. | Coldspring, TX 77331 | Oil & Gas Operator | May 2025 |
| 353 | Jilpetco, Inc. | Fort Worth, TX 76121 | Oil & Gas Operator | May 2025 |
| 354 | JJRS Investments Inc. | Corpus Chrsti, TX 78409 | Oil & Gas Operator | May 2025 |
| 355 | JMC Resources Corp. | Houston, TX 77077 | Oil & Gas Operator | May 2025 |
| 356 | JMM Energy LLC | Brownsville, TX 78521 | Oil & Gas Operator | May 2025 |
| 357 | Josey, Lenoir M., Inc. | Houston, TX 77019 | Oil & Gas Operator | Aug 2003 |
| 358 | JRP Production, LLC | Boling, TX 77420 | Oil Operator | May 2025 |
| 359 | K-B Exploration Co. | Houston, TX 77057 | Oil & Gas Operator | May 2025 |
| 360 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | May 2025 |
| 361 | Kaler Energy Corp. | Boerne, TX 78006 | Oil & Gas Operator | May 2025 |
| 362 | Karbuhn Oil Company | Tomball, TX 77375 | Oil & Gas Operator | May 2025 |
| 363 | Karper Company, The | Graham, TX 76450 | Oil & Gas Operator | Feb 2003 |
| 364 | Karper Oil & Gas Corporation | Graham, TX 76450 | Oil & Gas Operator | May 2025 |
| 365 | Katy Resources LLC | Arlington, TX 76016 | Oil & Gas Operator | May 2025 |
| 366 | KCS Resources, Inc. | Houston, TX 77002 | Oil & Gas Operator | Feb 2009 |
| 367 | Kebo Oil & Gas, Inc. | Portland, TX 78374 | Oil & Gas Operator | May 2025 |
| 368 | Kelso Oil LLC | Chase, KS 67524 | Oil & Gas Operator | Apr 2007 |
| 369 | Kem Energy, Inc. | Katy, TX 77450 | Oil & Gas Operator | May 2025 |
| 370 | Ken Petroleum Corporation | Dallas, TX 75206 | Oil & Gas Operator | Feb 2019 |
| 371 | Kerr-McGee Oil & Gas Onshore LP | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 372 | Kling, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Dec 2000 |
| 373 | Klotzman, M. S. Exploration Co. | Victoria, TX 77903 | Oil & Gas Operator | May 2025 |
| 374 | Kraker & Martin Energy, L.L.C. | Tulsa, OK 74136 | Oil & Gas Operator | Apr 2011 |
| 375 | KWS Oil & Gas, LLC | El Campo, TX 77437 | Oil & Gas Operator | May 2025 |
| 376 | Lakehills Production, Inc. | Austin, TX 78701 | Oil & Gas Operator | May 2025 |
| 377 | Landmark Production Company | MC Gregor, TX 76657 | Oil & Gas Operator | Oct 2010 |
| 378 | Laurel Fuel Company | Jackson, MS 39206 | Oil & Gas Operator | Dec 1996 |
| 379 | Lavaca River Operating Co., LLC | The Woodlands, TX 77381 | Oil & Gas Operator | May 2025 |
| 380 | Layton Energy Inc. | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 381 | Leach, D.L.,Jr. | Edna, TX 77957 | Gas Operator | Oct 2007 |
| 382 | Legacy Operating Company, LLC | Dallas, TX 75205 | Oil Operator | Jun 2024 |
| 383 | Legend Natural Gas III, LP | Houston, TX 77094 | Oil & Gas Operator | Feb 2015 |
| 384 | Leonard Brothers Operating Co. | Fort Worth, TX 76101 | Oil & Gas Operator | May 2025 |
| 385 | Leonard, J. A. | Austin, TX 78734 | Oil & Gas Operator | May 2025 |
| 386 | Lighthouse Exploration, Inc. | Corpus Chrsti, TX 78473 | Oil & Gas Operator | Jul 2007 |
| 387 | Lighthouse Operating, Inc. | Corpus Chrsti, TX 78410 | Oil & Gas Operator | Jun 2021 |
| 388 | Linn Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Jan 2019 |
| 389 | Linn Operating, Inc. | Houston, TX 77002 | Oil & Gas Operator | May 2017 |
| 390 | Live Oak Op & Production, L.L.C. | Austin, TX 78759 | Oil & Gas Operator | Nov 2011 |
| 391 | Llewellin Operating Company, LLC | Houston, TX 77024 | Oil & Gas Operator | Dec 2017 |
| 392 | Lodi Drilling & Service Co. | Corpus Chrsti, TX 78426 | Oil & Gas Operator | May 2025 |
| 393 | Lomak Production Company | Fort Worth, TX 76102 | Oil & Gas Operator | Aug 1998 |
| 394 | Long Trusts, The | Kilgore, TX 75663 | Oil & Gas Operator | May 2025 |
| 395 | Louisiana Jordan Oil Co, Inc. | Lake Charles, LA 70602 | Oil & Gas Operator | Dec 2024 |
| 396 | LTX Productions, Inc. | Houston, TX 77095 | Oil & Gas Operator | Jul 2008 |
| 397 | M & R Exploration Company | Houston, TX 77074 | Oil & Gas Operator | Aug 2003 |
| 398 | M & S Exploration | El Campo, TX 77437 | Oil & Gas Operator | May 2025 |
| 399 | M. J. G., Inc. | Alice, TX 78333 | Oil & Gas Operator | Jul 2010 |
| 400 | Maggert Energy Corp. | Spring, TX 77387 | Gas Operator | Jun 1998 |