| 101 | Encana Oil & Gas (USA) Inc. | Denver, CO 80202 | Oil & Gas Operator | Oct 2020 |
| 102 | Energetics Inc | Englewood, CO 80155 | Oil & Gas Operator | Aug 1985 |
| 103 | Energy Transfer Crude Marketing LLC | Dallas, TX 75225 | Oil Operator | Jan 2025 |
| 104 | Enerquest Oil & Gas LLC | Oklahoma City, OK 73114 | Oil & Gas Operator | Feb 2025 |
| 105 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | May 2025 |
| 106 | Ernest Operating Company | Rockdale, TX 76567 | Oil & Gas Operator | May 2025 |
| 107 | Esenjay Petroleum Corp. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jul 1998 |
| 108 | Estate Oil & Gas Corp. | Dallas, TX 75206 | Oil & Gas Operator | Oct 2011 |
| 109 | Et Gathering & Processing LLC | Dallas, TX 75225 | Oil Operator | Dec 2024 |
| 110 | Everest Minerals Corp. | Corpus Chrsti, TX 78403 | Oil & Gas Operator | Apr 2001 |
| 111 | Everest Resource Company | Corpus Chrsti, TX 78403 | Oil & Gas Operator | May 2025 |
| 112 | Express Oil Co. | Hallettsville, TX 77964 | Oil & Gas Operator | May 2025 |
| 113 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |
| 114 | Exxon Mobil Corporation | Spring, TX 77389 | Oil & Gas Operator | May 2025 |
| 115 | Fenn, Bill Inc. | Giddings, TX 78942 | Oil & Gas Operator | Mar 2008 |
| 116 | Field Petroleum Corp. | San Antonio, TX 78216 | Oil & Gas Operator | May 2025 |
| 117 | Finley Resources Inc | Fort Worth, TX 76113 | Oil & Gas Operator | May 2025 |
| 118 | Foothill Energy, LLC | Spring, TX 77393 | Oil & Gas Operator | May 2025 |
| 119 | Forest Oil Corporation | Houston, TX 77002 | Oil & Gas Operator | Mar 2015 |
| 120 | Fortune Natural Resources Corp. | Houston, TX 77067 | Oil & Gas Operator | Dec 2003 |
| 121 | Four C Oil & Gas Corp. | Dallas, TX 75206 | Oil & Gas Operator | Jan 2024 |
| 122 | Frostwood Energy, LLC | Houston, TX 77219 | Oil & Gas Operator | May 2025 |
| 123 | Future Petroleum Company LLC | Houston, TX 77027 | Oil & Gas Operator | Jun 2013 |
| 124 | Gaither Petroleum Corporation | Katy, TX 77493 | Oil & Gas Operator | May 2025 |
| 125 | Gantt Operating Company, Inc. | Houston, TX 77018 | Oil & Gas Operator | May 2025 |
| 126 | Gary Oil & Gas | Deer Park, TX 77536 | Oil & Gas Operator | May 2025 |
| 127 | Gasper Rice Resources, LTD. | Houston, TX 77068 | Oil & Gas Operator | May 2025 |
| 128 | Gemini Exploration Company | Dallas, TX 75219 | Oil & Gas Operator | Mar 1997 |
| 129 | Geo-Graphic Production, Inc. | Gonzales, TX 78629 | Oil & Gas Operator | May 2025 |
| 130 | Geosouthern Energy Corporation | The Woodlands, TX 77380 | Oil & Gas Operator | May 2025 |
| 131 | Ginger Petroleum Company, Inc. | La Grange, TX 78945 | Oil & Gas Operator | May 2025 |
| 132 | Glenco Oil & Gas Company | Seguin, TX 78155 | Oil & Gas Operator | Dec 1994 |
| 133 | Glenn, Wayne E. & Assoc., Inc. | Dickinson, TX 77539 | Oil & Gas Operator | Jun 2005 |
| 134 | Great West Energy & Expl., Inc. | Addison, TX 75001 | Oil & Gas Operator | Mar 2008 |
| 135 | Greenbriar Energy Inc. | Houston, TX 77098 | Oil & Gas Operator | Feb 2004 |
| 136 | Gulfstar Properties, Inc. | San Antonio, TX 78229 | Oil & Gas Operator | May 2025 |
| 137 | H - A Energy, Inc. | Midland, TX 79704 | Oil & Gas Operator | May 2025 |
| 138 | Hallwood Petroleum, Inc. | Midland, TX 79701 | Oil & Gas Operator | Jan 2025 |
| 139 | Hampton Resources Corporation | Houston, TX 77010 | Oil & Gas Operator | Mar 1996 |
| 140 | Harbor Resources LLC | Oklahoma City, OK 73120 | Oil & Gas Operator | May 2025 |
| 141 | Harvey Brothers Oil & Gas | Corpus Chrsti, TX 78408 | Oil & Gas Operator | Jul 2004 |
| 142 | Heartland Resources, Inc. | Temple, TX 76501 | Oil & Gas Operator | Mar 2008 |
| 143 | Herd Producing Company, Inc. | Tyler, TX 75711 | Oil & Gas Operator | May 2025 |
| 144 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | May 2025 |
| 145 | HK Energy Operating, LLC | Houston, TX 77002 | Oil & Gas Operator | May 2023 |
| 146 | Holifield Oil Company | Giddings, TX 78942 | Oil & Gas Operator | Mar 2009 |
| 147 | Hollub Production Company | Seguin, TX 78156 | Oil & Gas Operator | Jul 2000 |
| 148 | Hollub, Lambert Drilling Company | Seguin, TX 78155 | Oil & Gas Operator | May 2025 |
| 149 | Home Petroleum Corp | Victoria, TX 77902 | Oil & Gas Operator | May 2025 |
| 150 | Houston Oil & Minerals Corp. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 151 | Houston Petroleum Company | Houston, TX 77027 | Oil & Gas Operator | May 2025 |
| 152 | HRH Energy Group Incorporated | Carrollton, TX 75006 | Oil & Gas Operator | Nov 2009 |
| 153 | Hurd Enterprises, LTD. | San Antonio, TX 78209 | Oil & Gas Operator | May 2025 |
| 154 | Impetro Operating LLC | Fort Worth, TX 76102 | Oil & Gas Operator | Nov 2020 |
| 155 | Ironroc Energy | The Woodlands, TX 77381 | Oil & Gas Operator | May 2025 |
| 156 | J C Petroleum Inc | Chickasha, OK 73023-1433 | Oil & Gas Operator | Dec 2013 |
| 157 | J.W. Service Company | Smithville, TX 78957 | Oil & Gas Operator | May 2025 |
| 158 | Jda Energy, LLC | Houston, TX 77058 | Oil & Gas Operator | May 2025 |
| 159 | Jenkins Oil Corporation | Hankamer, TX 77560 | Oil & Gas Operator | Mar 2008 |
| 160 | JN Exploration & Production LP | Billings, MT 59103 | Oil & Gas Operator | Jan 2001 |
| 161 | Kaiser-Francis Oil Company | Tulsa, OK 74121 | Oil & Gas Operator | May 2025 |
| 162 | Karbuhn Oil Company | Tomball, TX 77375 | Oil & Gas Operator | May 2025 |
| 163 | Kelpetro, Inc. | Houston, TX 77056 | Oil & Gas Operator | Mar 2012 |
| 164 | Keystone Exploration, Inc | College Sta, TX 77845 | Oil & Gas Operator | May 2025 |
| 165 | Killam Oil Co., LTD. | Laredo, TX 78042 | Oil & Gas Operator | May 2025 |
| 166 | KP Exploration, Inc. | Houston, TX 77002 | Oil & Gas Operator | Apr 1997 |
| 167 | L & R Drilling Company | Belle Fourche, SD 57717 | Oil & Gas Operator | Dec 1999 |
| 168 | Lacy, F. B. Inc. | Houston, TX 77055 | Oil & Gas Operator | Sep 1997 |
| 169 | Lario Oil & Gas Company | Odessa, TX 79762 | Oil & Gas Operator | May 2025 |
| 170 | Le Bas Operating Company, Inc. | Giddings, TX 78942 | Oil & Gas Operator | Mar 2000 |
| 171 | Leexus Oil & Gas L.L.P. | Giddings, TX 78942 | Oil & Gas Operator | Jun 2008 |
| 172 | Leexus Oil LLC | Giddings, TX 78942 | Oil & Gas Operator | May 2025 |
| 173 | Leexus Operating Company | Austin, TX 78734 | Oil & Gas Operator | Aug 2007 |
| 174 | Leonard, J. A. | Austin, TX 78734 | Oil & Gas Operator | May 2025 |
| 175 | Lindow Oil & Gas, LLC | Caldwell, TX 77836 | Oil & Gas Operator | May 2025 |
| 176 | Live Oak Gas Company | Dallas, TX 75251 | Oil & Gas Operator | May 2025 |
| 177 | Loin Energy Corporation | La Grange, TX 78945 | Oil & Gas Operator | May 2025 |
| 178 | Longhorn Mineral Corporation | Bellaire, TX 77401 | Oil & Gas Operator | May 2018 |
| 179 | Lynco Oilfield Equipment, Inc. | Giddings, TX 78942 | Oil & Gas Operator | Aug 2003 |
| 180 | M W Production Co. | New Braunfels, TX 78130 | Oil & Gas Operator | Aug 2003 |
| 181 | M. K. Production | Caldwell, TX 77836 | Oil & Gas Operator | Mar 2008 |
| 182 | Magna Oil & Gas Corporation | Irving, TX 75017 | Oil & Gas Operator | Feb 2016 |
| 183 | Magnolia Oil & Gas Operating LLC | Houston, TX 77046 | Oil & Gas Operator | May 2025 |
| 184 | Magnum Producing & Operating Co. | Corpus Chrsti, TX 78471 | Oil & Gas Operator | Jan 2004 |
| 185 | Magnum Producing, LP | Corpus Chrsti, TX 78401 | Oil & Gas Operator | May 2025 |
| 186 | Mai Oil Operations, Inc. | Dallas, TX 75225 | Oil & Gas Operator | Jan 2025 |
| 187 | Majestic Petroleum Corporation | Dallas, TX 75230 | Oil & Gas Operator | Oct 1996 |
| 188 | Marathon Oil Company | Houston, TX 77252 | Oil & Gas Operator | Mar 2025 |
| 189 | Mariah Energy Corp. | Austin, TX 78716 | Oil & Gas Operator | Apr 1999 |
| 190 | Matrix Petroleum, LLC | Houston, TX 77077 | Oil & Gas Operator | May 2025 |
| 191 | Maverick Prod. Co., Inc. | Houston, TX 77056 | Oil & Gas Operator | May 2025 |
| 192 | MBR Resources, Inc. | Tulsa, OK 74119 | Oil & Gas Operator | May 2025 |
| 193 | McCarthy Oil & Gas Corporation | Houston, TX 77056 | Oil & Gas Operator | Oct 2007 |
| 194 | McCulliss Resources Co Inc | Littleton, CO 80161-3248 | Oil & Gas Operator | Jun 2009 |
| 195 | McDaniel Company, Inc., The | Dallas, TX 75230 | Oil & Gas Operator | May 2025 |
| 196 | McDonald Production | Lubbock, TX 79408 | Oil & Gas Operator | Mar 2003 |
| 197 | McQueen Ed & Company Inc | Lindsey, OK 73052 | Oil & Gas Operator | Apr 2014 |
| 198 | McRae & Henry LTD | Golden, CO 80401 | Oil & Gas Operator | May 2022 |
| 199 | Melton, Joe, DRLG. Co., Inc. | Midland, TX 79704 | Oil & Gas Operator | Dec 2004 |
| 200 | Merica Oil Operating Company | Frisco, TX 75034 | Oil & Gas Operator | Sep 2024 |