If someone has a community on Discord that they're hoping to migrate away, these are some tools that could potentially help.
This is just a list. I haven't investigated these options. They could be useless.
Discord SSO via OAuth2 https://discord.com/developers/docs/topics/oauth2This might help ensure that you have the same userbase on Discord as on the other service.
It could help a smooth transition.
MatrixOAuth for Matrix
https://github.com/turt2live/matrix-oauthMatrix Jitsi stuff
https://matrix.org/blog/2020/04/06/running-your-own-secure-communication-service-with-matrix-and-jitsiMatrix SIP stuff
https://matrix.org/blog/2014/11/30/bridging-matrix-sip-via-vertoMumble/MurmurMumble SIP
https://github.com/slomkowski/mumsiMumble Web
https://github.com/Johni0702/mumble-webWhat else would help migrate a Discord community?