I've been doing this at my co-op, just as a kind of, I don't know, break from capitalism or something? Or maybe to practice getting users before finding a monetizable project? Most are rinky dink derp projects to let co-op members play around with whatever stack, or to give potential members a project they can get a commit on (requirement to join), but some I think are kinda useful. Some I use every day, like the calorie one.

None of these run ads or make any money so I'm going to share them guiltlessly:

https://calories.508.dev just a simple average calorie tracker over months. I couldn't find anything like this online or on the app store.

https://travelcards.508.dev Generate printable cards with localized allergies or whatever for trips. Apparently a lot of our wedding guests like this. https://github.com/508-dev/travel-cards

http://stuff4friends.508.dev A stuff library for your friends to borrow stuff you aren't using. I'm most excited about this one right now because I have so much stuff, and my friends seem to be enjoying borrowing random stuff they wouldn't have just because they can see it and know it's all being tracked. https://github.com/508-dev/friend-library