All Hands: This non-profit recommended to Vox by disasterologist Samantha Montano has staff on the ground in Texas, and is in contact with emergency management officials about assisting in the response and recovery. You can give here. (4/4 stars from Charity Navigator.)
Global Giving: A charity crowdfunding site that is attempting to raise $2 million to be used exclusively for local relief and recovery efforts. You can give here. (4/4 stars from Charity Navigator.)
Foundation Beyond Belief: The humanist group, also recommended by Montano, is evaluating how best to use the funds that they collect. You can give here.
Greater Houston Community Fund: A broad-based relief fund established by Houston Mayor Sylvester Turner. You can give here.
Houston Humane Society: The group is helping marshal care and shelter for pets in the area. You can give here. The Society for the Prevention of Cruelty to Animals of Texasis undertaking similar efforts. You can give here. The San Antonio Humane Society is doing the same. More here.
Americares: The non-profit focused on medicine and health is seeking to provide emergency medical supplies and other basic resources to first responders and others in Texas. You can give here. (4/4 stars from Charity Navigator.)
Portlight: A disaster response group dedicated specifically to people with disabilities. They are seeking to help affected people with evacuation and finding shelter, any medical equipment needs they might have, and more. You can learn more about their efforts here.
SBP: The New Orleans-based organization is planning to send Americorps volunteers, assist local leaders and nonprofits, and eventually help rebuild damaged or destroyed homes. You can give here. (4/4 stars from Charity Navigator.)
AirBNB: The hospitality company is working to coordinate people in need of a place to stay with people willing to offer a free room. More information here.