“Master rigger” is a job or training title used by some employers and training companies. It is not one universal credential with the same rules everywhere. In industrial work, the person in that role is usually expected to understand complex lifts, load control, equipment selection, inspection, rigging math and safe lift planning.
Do not choose a class by the biggest title on the page. Ask which credential the course prepares you for and what the employer requires. Rig Right Texas focuses on the NCCER Advanced Rigger path, with live instruction and hands-on preparation near Corpus Christi.
If you are already the person your crew trusts when a lift gets complicated, it may be time to document what you know. Review the Advanced Rigger class before another opportunity passes you by.