I'm apparently too lazy to write Wikipedia articles, but not too lazy to identify needed articles. In cases where I have links that may be helpful to article writers, I've included them.
Center for Security and Emerging Technology (CSET)
Think tank at Georgetown University launched in 2019 with a $55m grant from the Open Philanthropy Project.
Animal Charity Evaluators
Has a sentence in the main EA article.
Centre for Effective Altruism
Forethought Foundation / Global Priorities Institute
Organizations associated with William MacAskill.
Effective Altruism Foundation / Stiftung für Effektiven Altruismus
Parent organization of Raising for Effective Giving and other projects.
The AI Does Not Hate You
New book by Tom Chivers just released in the UK. Focused on AI risk and the rationality movement, but covers EA and EA-relevant AI safety organizations.
Machine learning research organization that has received grants from the Long Term Future Fund and the Open Philanthropy Project. Note: there currently do not seem to be any news or magazine articles about it, which may be an obstacle to a Wikipedia article.
Center for Human-compatible AI (CHAI)
UC Berkeley research group funded by the Open Philanthropy Project and others.
Kelsey Piper / Future Perfect
Future Perfect has a paragraph in the main EA article.