I don’t know of any either and I’m on like 40+ servers probably. I’ve run our weekly dnd on it for years without issue after trying the other options. Get that it’s not good for tracking and documentation in any official capacity but it’s pretty damn good for active niche interest communities.
The music production servers I’m on are a perfect use of the platform IMO. There’s a server run by a guy who manufactures an open source tracker device, and there’s channels where people post works in progress, get help from others, there’s streaming events where people can submit songs they’ve made using the device, etc. There’s a bunch of people popular in the music scene who regularly help noobs. Always ongoing active discussions, everyone is polite, there’s a lot of knowledge shared in real time.
So when people are like “Discord sucks use my favorite platform instead,” I’m just like I don’t even care about the platform I just wanna be where some cool shit is happening and your platforms are fucking boring. Show me the cool servers on your platform then so I actually want to use it. It’s the idea of these platforms people like, and I like it too, my close social group uses a privately hosted Matrix service which I use every day, but I’ve never found a comparable community on these services outside of this use case.