A subscription service for open source projects. As a company I would pay you monthly and get access to bug and features development for all the open source dependencies that I am using. The more I pay the more things I can get done in a month. If a feature is too big for my budget I can accumulate month to month value on a ticket or get other companies to participate.
Furthermore, a project maintainer could put on his README, that, for a certain recurring donation, you get some level of direct personal contact.