Patrick McKenzie (patio11), who famously built and sold his "Bingo Card Creator", and blogged about the process, is a "prototypical" Indie Hacker.
The ecosystem consists of communities like [1] and [2], podcasts (search for "Indie Hackers"), and conferences like [3]
[0] https://training.kalzumeus.com/newsletters/archive/selling_s...
[1] https://www.indiehackers.com/
[2] https://getmakerlog.com/
[3] https://microconf.com/