From the back of my mind I would say: Patreon, foundations, Open Collective and Tidelift, but it's clearly not enough for everyone.
This is a good article on the topic: Open source sustainability
Henry Zhu in this post on dev.to talks about this topic too:
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.