I can think of:
- CentreForEffectiveAltruism.org (EA Forum)
- LightconeInfrastructure.com (LessWrong)
- OurWorldInData.org
- Metaculus.com
- Ought.com
- 80,000 Hours' Job Board
- GiveMomentum.com
- Wave.com
- Sparkwave.tech
- QURI
- Vegan Hacktivists
Self-promotion is welcome :)
I posted the same question 1 year ago.