Review
The main funders are LTFF, SFF/Lightspeed/other S-process stuff from Jaan Tallinn, and Open Phil. LTFF is the main one that solicits independent researcher grant applications.
There's a lot of orgs, off the top of my head, there's Anthropic/OpenAI/GDM as the scaling labs with decent-sized alignment teams, and then there's a bunch of smaller/independent orgs:
And there's always academia.
(I'm sure I'm missing a few though!)
(EDIT: added in RR and CLR)
Very surprised that you don't have a regranting budget! I don't know which funder I would expect to do that, but I would've expected this to be more common.
I guess Jan Tallinn does this, and Manifund does this. Hmm.
Depending on the kind of support they're looking for https://ceealar.org could be an option. At any one time there are a handful of people staying there working independently on AI Safety stuff.
It sometimes happens that people who I've talked to or worked with ask me where they should go for financial support for their research. I haven't developed a standard list of answers to this question. It seems to me like there are a lot of new orgs recently, and I'm losing track!
If you are looking for such applicants or know someone who is looking, consider replying as an answer (or sending me a PM if that makes more sense for whatever reason).