Rainforest connection reprograms used android phones to listen for illegal logging in protected rainforests, and then send real-time notifications to law enforcement to intervene. It works, and they have already saved a tremendous amount of rainforest. They are doing good and important work; please support them in any way you can.
Women on Waves/Women on Web
This organization provides abortion pills to women who need them in countries where it is still illegal to have abortions. Additionally, they are providing the service for free to anyone who has tested positive for Zika.