Dan Aramov ran Patron campaign to raise money to work on developing Redux.js full time https://web.archive.org/web/20150721215514/https://www.patre...
And then there's Andrew Godwin raising £17,952 to work on Schema Migrations in Django https://www.kickstarter.com/projects/andrewgodwin/schema-mig...
Asking for money for open source software does work.