Let me start by saying, it might not be the best idea to come into Texas from out of state to, say, protest. Texans, and I mean in general not just the ones that tend to vote all Red, tend to be… leery of outsiders coming and dictating our policies and tend to recoil and become defensive if this happens. It’s easy to help from afar and help homegrown advocacy and assistance groups and trans people directly affected by our laws.
Here’s some orgs to look into:
Equality Texas: Highly rated LGBTQ advocacy group. If you support only one group, ET is maybe the best
Trans Education Network of Texas (TENT): Another local group that is focused on advocating for trans Texans and educating cis people on trans issues, they are focused just on trans issues if that’s what you want to focus on.
OutYouth: Offers a physical safe haven for LGBTQ kids in the Austin area. It’s been around as long as I’ve been alive.
ACLU of Texas: The ACLU’s Texas branch which has been on the ground fighting against transphobic bills from day 1
Texas Health Action: Runs Kind Clinic which offers free transition related care and other resources for the LGBTQ community in Texas, based in Austin, San Antonio, and Dallas
