I just had my account deactivated from Discord for ToS violation (I didn't do anything wrong, I just tried to send a friend request), but that's not the most important thing.
Now that I no longer have an account, and I've been wanting to leave Discord for a while for a better, self-hosted, open-source alternative, this is the best time.
I know of Matrix, XMPP servers and applications that work very well, but none of them work in the same way, or have the same feel as Discord. I see more alternatives for professional use than for gamers or communities.
Revolt exists, but last time I checked, you can't really host it yourself, and I haven't read good things about it. (I don't remember the website listing all the negative aspects.)
That brings me to my two questions.
Can you list some alternative to Discord that I probably don't know ?
If you want a alternative to Discord, what are your requirements to using it ? I'm not saying I can or will, but I think I can try to create one.
PS: I already trying to get my account back (but I have the same response from the support and I can't send request to "Appeals & Age Update Requests" because of ToS violation) and even if I manage to get it back I really want to leave discord right now.
Look into mumble. It's NOT a discord replacement but does provide a good quality, low latency, OSS voice chat. Mumble + Signal group chat is what my friends and I use for gaming. Seems to work well.
The "problem" is that most people only want an app that does everything, and I'm sure some of my friend don't want to have two app to do the same thing one app can do.
I prefer to have two perfect app for one task, but not everyone want this.
Programs that do multiple things are not simple, so successfully using or understanding what they do is less likely to be possible for you. I expect that wanting to avoid interacting with many programs will lead a person to use programs that are nonfree more often than they otherwise would, so it would be more likely that a program controls the users.