The Texas Insurance Code, chapter 1501: https://statutes.capitol.texas.gov/Docs/IN/htm/IN.1501.htm
The Texas Administrative Code, Title 28, chapter 26, subchapter A: https://texreg.sos.state.tx.us/public/readtac$ext.ViewTAC?tac_view=5&ti=28&pt=1&ch=26&sch=A&rl=Y
Many of the rules are no longer applicable as the Affordable Care Act is more protective of the consumer. However, in areas where there is no conflict, or where Texas law is more protective of the consumer, the state law still applies.