https://www.firstmonday.org/ojs/index.php/fm/article/view/67...
Kickstarter's "project is funded when enough people commit" is another, though Kickstarters don't usually produce public or open source works.
In general these are considered "threshold pledge systems":
https://en.m.wikipedia.org/wiki/Threshold_pledge_system
Whether the thing being funded is a rivalrous good or a public one, this pattern solves the problem of latent demand by derisking the transaction to overcome the reluctance to commit unless the expenditure will make a difference.
Applying the pattern episodically, and you get Patreon's ongoing pledge per work produced. Apply the pattern recursively and you get Kickstarter's stretch goals. Combine the price discrimination pattern one way and you get pledge/reward levels. Use price discrimination another way (particularly for public goods) and you get "early access".
There are probably other interesting and useful variations that are still yet to be discovered.
When it came free with no effort, it has no value and therefore it takes a real effort to understand that the maintainer and others may not see it the same way.
open source software gives you, the user, the responsibility for you use of it; where most people want that to be someone else's job. They want to jump on the gokart and ride, not check the tire pressures, tune the engine, etc.