I preferred Flattr's model - you just donated a fixed amount per month, and they divided it by project. But it wasn't indiscriminate - you had to click on a button for each project. Now it seems they use a "smart, privacy-friendly algorithm [which] measures attention on websites", which is a no-go for me.

The problem with indiscriminate is that there are many, many, many OS projects out there. You need some curation, and that opens a can of worms. Maybe they could allow people to share and use lists?