This is great Sean - thanks for the links too, there was some I was not aware of here. I have one other extreme example, which probably is not meant to be replicated in too many places, but it does massively emphasise the point of shipping early, charging early and all that fun stuff.
Pieter Levels is quite well known in the Indie Maker/Bootstrapped world. He had a few successful products before and decided he wanted to write a book about bootstrapping business.
He created a landing page - literally a typeform - announcing the book, stating it hadn’t been started yet and asking people to support it for something like $20. He quickly made $50k and then shared a doc with all the people who had ordered and asked them what they wanted in the book.
Again just shows an extreme example of getting in front of customers and building/delivering what they want rather than what you think they want.
Some more info about the makebook story here