The Effective Altruism movement is currently closely connected to GiveWell because it is the only organization that's trying to answer the question "where can my money do the most good?" Unfortunately, when people don't agree with GiveWell's values this tight connection can lead them to reject the whole idea of evaluating charities on outcomes and comparing across causes. While I think GiveWell's values and outlook are very reasonable, founding additional charity evaluators trying to answer the same basic question from the perspective of different value systems would be very useful.

(The closest I currently see to this is Effective Animal Activism. It's a charity evaluator for people who think animals matter a lot. [1] Their current evidence is not very strong [2] but I'm excited about the experiments they're running now (though I do have some concerns) and did some volunteer surveying for them.)

[1] GiveWell's view on animals is "We also place value on reducing animal's suffering, though our guess is that the type of suffering animals experience is of a kind that we would not weigh as heavily as the type of suffering that humans experience." I would go farther, and say that I'm not sure the type of suffering animals experience matters at all.

[2] They are based on surveys which I have found various problems with, primarily missing control groups.