[remslave]

Matrix/Element seems the best drop-in replacement for Discord. Can set up chatrooms in Discord "server"-style, or as persistent DMs with others. In the chatrooms, you can make text chat spaces and call spaces. No dedicated voice chat space, you just dont turn on webcam for the call spaces. Pretty sure it uses same voip tech. Selfhostable if you want. Encrypted. Really it is just a barebones but functional Discord. Matrix can be bridged to Discord as well so you can talk between either, should help ease the transition period for anyone jumping ship.

[conception]

Stoat, Zulip, and Mattermost are other options.

Element was a bit too raw for me - mobile wasn’t great either. Ymmv

[happymellon]

Hasn't Mattermost already done one bait and switch?

I don't use it but IIRC there was an uproar a couple of months ago about them just switching up message history and deleting conversations.

[hackable_sand]

Zulip is definitely not an alternative to discord but I'll check out the others.

[foxrider]

For mobile, you can use FluffyChat, it's another Matrix app

[soupbowl]

I like matrix and use it but it is no where near a Discord replacement. Setting up the modern Matrix auth and call are not easy and its just not as good or easy as Discord.