results (sorted by most suggested):
* matrix (6 suggestions)
* mattermost (3 suggestions)
* irc (2 suggestions)
* mumble (1 suggestion)
* wire (1 suggestion)
@lizardsquid maybe an alternative might be an XMPP app that wraps different channels/servers to a single interface?
@lizardsquid of these i use only wire. i'm not sure i'd call any of them alternatives to discord tho really...