Just a small handful of my favorites:
- Simple Analytics by Adriaan van Rossum, making $2900/month (http://bit.ly/35QXFhY). Competing with Google Analytics and tons of well-funded competitors isn't easy, but Adriaan's focus on privacy and simplicity has a strong appeal.
- Maker Mind by Anne-Laure Le Cunff, making $800/month (http://bit.ly/31FYK97). She's a neuroscience student and ex-Googler who writes fascinating articles about the intersection of neuroscience, entrepreneurship, and productivity.
- Makerpad by Ben Tossell, making $24000/month (http://bit.ly/2JeIEg9). Makerpad helps non-developers build complex apps where you'd typically expect developers to be required. My favorite thing about Ben is that he basically refuses to run a business that's not 100% enjoyable. He's shut down a working company or two just because the business model wasn't shaping up to be something he was excited about in the long run.
- Key Values by Lynne Tye, making $25000/month (https://www.keyvalues.com). Lynne helps developers find roles at companies that share their values, and she shares a ton of helpful tips for job-seekers in her newsletter. Her business model involves charging companies to put together the super in-depth profiles on her site.
- Carrd by @ajlkn, making over $30000/month (https://carrd.co). Card is a one-page site builder. AJ's an amazing developer/designer combo with over a decade of experience building one-page website templates and builders. I can't name any web apps I've found easier to use and more polished than Carrd, so it's not surprising AJ has many thousands of paying customers.
- Starter Story by Pat Walls, making $7100/month (http://bit.ly/35XdALQ). Pat interviews e-commerce founders about how they started their businesses. He was inspired by Indie Hackers itself and monetizes via sponsorships. Some people think you can't get an advertising model to work as a solo founder, but it's actually quite great if you're not afraid to do a little sales. Not only do you get to know your advertisers personally, but you can also hand-code your ads into your site instead of installing third-party JS that will track your visitors all over the web.
It's late so I'll stop here, but there are many thousands more.
The Internet obviously makes it easy to connect to millions of people across the world, which enables all sorts of niche businesses to exist that previously wouldn't have worked, because you couldn't have found critical mass in just your local environment. Plus it's cheaper and easier than ever to build and host your own apps.
I think this is the future, and 10 years from now we'll see a staggering number of people (mostly devs) running their own one-person businesses instead of working jobs.