Here is a list of some organizations that you may be interested in.
At the national level:
* 50CAN
* Center for Education Reform (Their parent power index is especially interesting!)
* National Association for Gifted Children
At the state level:
* Raise Your Hand Texas (RYHT) (Note: Raise Your Hand Texas formally opposes any type of private school choice)
* Texans Advocating for Meaningful Student Assessment (TAMSA)
* Texans for Education Opportunity (TEO)
* Texas Charter School Association (TCSA)
* Texas Parent PAC (Note: Texas Parent PAC formally opposes any type of private school choice)
* Texas PTA (Note: Texas PTA formally opposes any type of private school choice)
* Texas Association for the Gifted and Talented (TAGT) (Note: TAGT formally opposes any type of private school choice)