From PPI
PPI and many of its Members have a number of Resources that can be used by others:
Pads
Meeting Servers
Mumble
mumble://mumble.ppi.rocks/
mumble://mumble.piratenpartei-nrw.de/
mumble.piratenpartei-bayern.de
mumble://talk.parley.be https://talk.parley.be/
Jitsi