| 1 | E & E Production Company, Inc. | | Oil & Gas Operator | Dec 2004 |
| 2 | E. & S. Drilling Company | | Oil & Gas Operator | Feb 1995 |
| 3 | Ed I. Estis | | Oil & Gas Operator | Sep 1998 |
| 4 | Edwin L. Cox | | Oil & Gas Operator | May 1986 |
| 5 | Edwin L. Cox & Berry R. Cox | | Oil & Gas Operator | Jun 1986 |
| 6 | Eex Corporation | Houston, TX 77060 | Oil & Gas Operator | Feb 2000 |
| 7 | Elad Petroleum Corporation | | Oil Operator | Jun 2005 |
| 8 | Energy Corp. Of America, Inc. | | Oil & Gas Operator | Aug 1998 |
| 9 | Energy Development Corporation | Houston, TX 77067 | Oil & Gas Operator | Dec 2023 |
| 10 | Energy Research & Dev. Corp. | | Oil & Gas Operator | Feb 1998 |
| 11 | Energy Sources, Inc. | | Oil & Gas Operator | Nov 1990 |
| 12 | Enervest Operating LLC | Houston, TX 77002 | Oil & Gas Operator | Nov 2024 |
| 13 | Enserch Exploration Inc | Dallas, TX 75206 | Oil & Gas Operator | Apr 2015 |
| 14 | Entex Petroleum, Inc. | Oklahoma City, OK 73113 | Oil & Gas Operator | Nov 1997 |
| 15 | Entex, Inc. | | Oil & Gas Operator | Dec 1984 |
| 16 | EP Operating Co. | Dallas, TX 75201 | Oil & Gas Operator | Jan 1993 |
| 17 | Equitable Petroleum Corp. | | Oil & Gas Operator | Jan 1999 |
| 18 | Et Gathering & Processing LLC | San Antonio, TX 78258 | Oil Operator | Jun 2024 |
| 19 | Etc Texas Pipeline, LTD. | San Antonio, TX 78258 | Oil Operator | Sep 2023 |
| 20 | Excalibur Operating, LLC | | Oil & Gas Operator | May 2024 |
| 21 | Exchange Oil & Gas Corporation | Tulsa, OK 74103 | Oil & Gas Operator | Oct 1987 |
| 22 | Extex Operating Company | Houston, TX 77057 | Oil & Gas Operator | Nov 2024 |
| 23 | Exxon Corporation | Houston, TX 77210 | Oil & Gas Operator | Jun 2024 |