| 1 | H.E.R. Operating, LLC | Silsbee, TX 77656 | Oil & Gas Operator | Mar 2025 |
| 2 | Halcon Operating Co., Inc. | Houston, TX 77024 | Oil & Gas Operator | Mar 2025 |
| 3 | Hamill, Claud B. Estate Of | Houston, TX 77002 | Oil & Gas Operator | Nov 1995 |
| 4 | Hamman Oil & Refining Company | Houston, TX 77098 | Oil & Gas Operator | Mar 2025 |
| 5 | Hanson Minerals Co. | Houston, TX 77042 | Oil & Gas Operator | Oct 1993 |
| 6 | Hanson Production Company | Cuero, TX 77954 | Oil & Gas Operator | Jul 2009 |
| 7 | Harrison Interests, LTD. | Houston, TX 77002 | Oil & Gas Operator | Mar 2025 |
| 8 | Heritage Expl. & Prod. Co., Inc. | Stafford, TX 77497 | Oil & Gas Operator | Dec 2000 |
| 9 | Heritage Operating Co., Inc. The | Stafford, TX 77497 | Oil & Gas Operator | May 1997 |
| 10 | High Bluff Operating, LLC | Littleton, CO 80161 | Oil & Gas Operator | May 2018 |
| 11 | Hilcorp Energy Company | Houston, TX 77208 | Oil & Gas Operator | Mar 2025 |
| 12 | Hollimon Oil Corporation | Castroville, TX 78009 | Oil & Gas Operator | Nov 2016 |
| 13 | Houston Expl. & Prod. Co., Inc. | Austin, TX 78746 | Oil & Gas Operator | Aug 2003 |
| 14 | Houston Hydrocarbons, Inc. (A) | Houston, TX 77042 | Oil & Gas Operator | Sep 2004 |
| 15 | Houston Oil & Minerals Corp. | Houston, TX 77002 | Oil & Gas Operator | Aug 1996 |
| 16 | HRB Operating Company Inc | Bridgeport, TX 76426 | Oil & Gas Operator | Mar 2025 |
| 17 | Hughes, Dan A. Company | Beeville, TX 78104 | Oil & Gas Operator | May 2006 |
| 18 | Hunt Oil Company | Dallas, TX 75201 | Oil & Gas Operator | Mar 2025 |
| 19 | Hunt, WM. Herbert, Trust Est. | Dallas, TX 75201 | Oil & Gas Operator | Sep 1998 |
| 20 | Hunters Creek Oil & Gas | Houston, TX 77042 | Oil & Gas Operator | Mar 2025 |