I have one popular project I've worked since around 2010. Lately I've let some of the long time users who can also code maintain it though. It's a character creation editor for a game, a bit like second life in a way. (it's called pac3 for garrymsmod)

I don't have any numbers apart from steam workshop which claims 800k current subscribers, though that doesn't say anything about active users. But there are a lot of tutorials, discord groups, etc centered around this so I'd call it popular.

The way I maintain this project is not very professional. I maximize my own joy first because if I don't have that, I can't work on the project.

The community is loud, maybe because the community is also mostly young gamers. Sometimes I break things and people complain. Sometimes they can call me names, write long emotional posts about how I should revert something and how everything was better in the past version.

But overall I enjoy working on the project and seeing the amazing things people create with it that I could never foresee.

There are several channels for feature requests (github, discord, steamcommunity), but I don't actively follow it. I usually check when I'm not sure what to do but still feel like working on it.

Sometimes people contact me directly to ask if I can add X feature. Sometimes that works.

For features in general I try to implement something everyone can benefit from, since the editor allows you to create things from smaller building blocks, I'd rather make those smaller building blocks necessary to create the high level feature that was requested.