The Trevor Project
The Trevor Project is a hotline for young trans people in crisis. It's personally helped me many times come down from thoughts of self harm, suicide, and relapse related to gender dysphoria and general depression. It's staffed entirely by volunteers -- which means other trans people, queer people, or allies are on the other side of the phone.
Out Youth Austin
Texas has some of the strictest legislation in the country targeting trans youth, which is exactly the issue Out Youth works to solve -- it provides assistance to LGBT+ youth in Austin and the rest of Central Texas.
Lost N Found Youth Inc
Lost N Found Youth provides food, shelter, employment assistance, and healthcare assistance to LGBT+ youth in Atlanta, GA. There are a huge amount of homeless trans kids, and Lost N Found works to help get them fed, clothed, and into school or the workforce. They have their own shelter exclusively for young queer people, and also a thrift store you can shop at!
True Colors United
True Colors United works to provide shelter to trans youth in the states where they're most at-risk -- states like Texas, Florida, and Tennessee that have outsized populations of homeless transgender youth due to draconian legislation or transphobic cultural leanings.