Discord is an excellent, free, gaming-centric chat client that you can use on the web or run as a client on your computer.
I've been using the Discord Windows client for a few weeks now and I like it so much I'm switching to it for JDRGaming-related chat. Previously I was using IRC, but that was a bit tricky to set up for users. Discord is much simpler.
Here's an instant invite for the JDRGaming Discord server: https://discord.gg/5KVyRUv. I've added the Discord invite URL to each of the game servers, so you should see it when you join or during gameplay.