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)
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).