The runoffs in Georgia are absolutely the most important thing right now, and I encourage everyone to contribute as much as they can and get involved as much as they can. It cannot be said strongly enough how much of a difference it will make to the future of the country and the world if we win these two runoffs.
TL;DR: Donate to Block Power. It's the highest-leverage thing I know of right now.
I want to recommend a project I recently discovered that is (a) highly effective, (b) run by folks who care about evidence, and (c) relatively new thus unlikely to be saturated with funds.
1 Black voters support Democrats by huge margins, and black women even more so.
2 There are a massive number of eligible Black voters who didn't vote, enough to have easily defeated Trump in 2016.
• Pay volunteer Ambassadors in Black communities
• To recruit Vote Triplers among their friends
• Who each identify and remind three friends to vote
And they have a slick system:
• An app for Ambassadors that suggests people they are likely to know, to recruit as Vote Triplers
• A payment platform that instantly pays Ambassadors for each Vote Tripler they sign up
• An SMS platform that texts people to remind them to vote as election day approaches
This is the coolest thing I've heard of so far. It automatically scales up as more money is added to the pot, it reaches new communities of votes that are less likely to have been reached before, and it tends to grow geometrically because, naturally, once Vote Triplers hear that their friends are getting paid as Ambassadors, a good number of them want to sign up as Ambassadors too.