TLDR: The r/selfhosted subreddit has a Discord server. The owner’s account got hacked leaving the server in a precarious state. They submitted a support ticket, but Discord has not taken action in weeks and probably won’t at all, so they are considering starting a new Discord server.
Fluxer recently added self hosting and it has a mobile app in beta and soon to be released, admin from a web GUI, not difficult to host, and has a good amount of discord features. It is somewhat heavy though.