Runewriters has one! I ran a twitter poll beforehand asking how many people would be interested, and got about..... 50ish people who said they might join if I made one? I figured that was enough that it wouldn't feel completely dead, so I found some friends who were willing to help me mod and started it up! Patrons got kind of a sneak preview -- they were invited to the server first to make sure everything was working okay, and then I invited a few friends privately, and finally made a public invite for everyone a couple months later.
Since my comic isn't huge, I didn't feel a need to set up a whole bunch of safeguards for randos -- basically I have it so you can't preview links or post images into the chat until you get a role that marks you as "trusted," and once you've talked a bit in chat, me or one of the mods will give that role to you. It's basically just so that if some rando wants to barge in and spam something gross, there's a limit to how much damage they can do and it's relatively easy to clean up. This has never happened, but it feels nice to have a safeguard, haha.
It can go from really active on occasion to kinda quiet the rest of the time, and I generally describe it as chill! We ended up with a lot of gaming conversation early on, so I made a couple of channels for talking games or sharing stories about your latest D&D campaign when I saw there was a need for it. There's an art channel where everyone can share art, including me sometimes (a few folks in the chat have decided to learn to draw and share their progress, and that's been downright inspiring to watch). I also borrowed the idea from another chat I'm in of a "discussions" channel, which is an all-purpose place to sweep a conversation to if it's not good for the main chat -- a heavy serious topic, or spoilers for piece of media, etc. It doesn't get used a whole lot, but it's nice to have. And then I have the locked patron-only patreon channels!
I like it, and I'm happy I made it! It's been a fun place to hang out now and again. :>