International Community Foundation: This charity normally does a lot of work in Mexico, and is raising money for earthquake relief in a number of different areas in Mexico impacted by the two earthquakes that hit. You can give here. (4/4 stars from Charity Navigator.)
Global Giving: A charity crowdfunding site that is attempting to raise $1 million to be used exclusively for local relief and recovery efforts in Mexico. You can give to earthquake relief here. (4/4 stars from Charity Navigator.)
Red Cross Mexico: Usually the first group people think of when giving after a disaster. You can donate to the victims of Mexico City quake here, as well as the victims of the Chiapas and Oaxaca earthquakes here.
(A series of reports by ProPublica have raised questions as to how Red Cross uses its donations for emergency relief. You can find some of those stories here. Journalist Jonathan Katz also weighed in on the issue in an interview with Vox’s Sean Illing.)
UNICEF Mexico: The United Nations Children’s Fund specifically works to support children impacted by natural disasters, including building “child-friendly spaces” after disaster strikes. You can give here. (3/4 stars from Charity Navigator.)