This is the "safe bet" in my giving. They do a good job at improving lives, in the most effective way possible.
Center for Election Science - https://electionscience.org/
This is the "long shot" in my giving. Officeholders today are incentivized to carve out a slice of supporters, play to only that audience, and demonize everyone else. Approval voting is the best solution that I've seen. It's worked well in a few cities, but mainstream acceptance is a ways off.
Harvest.org
WorldWildlife.org