I wouldn't call this flag red, but maybe a yellow flag for Giving Green is that they've faced criticism for the quality of their research: https://forum.effectivealtruism.org/posts/7yN7SKPpL3zN7yfcM/why-i-m-concerned-about-giving-green – this is four years old at this point, so I wouldn't take it uncritically, and I think they are recommending different orgs now, but my advice would nevertheless be to do some legwork in figuring out whether the old criticisms still apply
I wouldn't call this flag red, but maybe a yellow flag for Giving Green is that they've faced criticism for the quality of their research: https://forum.effectivealtruism.org/posts/7yN7SKPpL3zN7yfcM/why-i-m-concerned-about-giving-green – this is four years old at this point, so I wouldn't take it uncritically, and I think they are recommending different orgs now, but my advice would nevertheless be to do some legwork in figuring out whether the old criticisms still apply
Possible addition - the Center on Long Term Risk have a fund for S-risk research
https://longtermrisk.org/grantmaking/
Thanks for taking the time to put this list together! :)
I left it off the list because I couldn't find evidence they were still making grants.