| 1 | T.D. Operating Company, Inc. | New Braunfels, TX 78130 | Oil & Gas Operator | Nov 1999 |
| 2 | Tanglewood Oil & Gas Co. | Gouldbusk, TX 76845 | Oil & Gas Operator | Oct 2025 |
| 3 | Taylor, Ben J. Inc. | Fort Worth, TX 76185 | Oil & Gas Operator | Feb 2022 |
| 4 | TDC Engineering, Inc. | Abilene, TX 79604 | Oil & Gas Operator | Oct 2025 |
| 5 | Tejones Operating Corporation | San Antonio, TX 78217 | Oil & Gas Operator | Oct 2025 |
| 6 | Tekna Synergy Corporation | Midland, TX 79702 | Oil & Gas Operator | Oct 2025 |
| 7 | Terrafina Energy, LLC | San Antonio, TX 78280 | Oil & Gas Operator | Oct 2025 |
| 8 | Tex-Lee Operating Company | Giddings, TX 78942 | Oil & Gas Operator | Oct 2025 |
| 9 | Texakoma Oil & Gas Corp | Dallas, TX 75240 | Oil & Gas Operator | Sep 2014 |
| 10 | Texana Operating Company | Houston, TX 77090 | Oil & Gas Operator | Oct 2025 |
| 11 | Texas Refining, Inc. | Houston, TX 77057 | Oil & Gas Operator | Aug 2003 |
| 12 | Texas Vanguard Oil Company | Austin, TX 78720 | Oil & Gas Operator | Jan 2014 |
| 13 | Texas-Ohio Producing Company | Spring, TX 77383 | Oil & Gas Operator | Jul 1995 |
| 14 | Thomas Oil & Gas Company | Luling, TX 78648 | Oil & Gas Operator | Aug 2003 |
| 15 | Thrall Operating Company, Inc. | Dallas, TX 75240 | Oil & Gas Operator | Oct 2025 |
| 16 | Three Forks Operating Co, LLC | Flatonia, TX 78941 | Oil & Gas Operator | Oct 2025 |
| 17 | Torch Operating Company | Houston, TX 77010 | Oil & Gas Operator | Mar 2015 |
| 18 | Tortuga Operating Company | Houston, TX 77055 | Oil & Gas Operator | Oct 2025 |
| 19 | Tracer Energy, Inc. | Graham, TX 76450 | Oil & Gas Operator | Nov 1998 |
| 20 | Tri-C Resources, Inc. | Houston, TX 77024 | Oil & Gas Operator | Aug 2009 |
| 21 | Triad Energy Corporation | Houston, TX 77057 | Oil & Gas Operator | Oct 2011 |
| 22 | Trinidad Petroleum, Inc. | Austin, TX 78711 | Oil & Gas Operator | Oct 2025 |
| 23 | Triple C Oil Inc. | Lockhart, TX 78644 | Oil Operator | Aug 2019 |
| 24 | Triple J Investments Inc | Longview, TX 75606 | Oil & Gas Operator | Feb 2023 |
| 25 | Trivista Operating LLC | Giddings, TX 78942 | Oil & Gas Operator | Oct 2025 |
| 26 | Tuskar (Texas), Inc. | Nichols Hill, OK 73116 | Oil & Gas Operator | Jan 2016 |