You might be interested in https://snowdrift.coop/ Their site/model is still evolving, but they've done some pretty good research on what other options there are already out there https://snowdrift.coop/p/snowdrift/w/en/othercrowdfunding .

As per the original question I don't think there is any such list of projects seeking donations and if there was one I doubt it would be concise. If you're personally interested in donating to a project via a subscription it shouldn't be that difficult to contact the maintainer to see if they'd be interested in receiving those donations and if they could setup some service to receive subscriptions.