@freesoftwarecaucus Forgive me for pointing this out, but we might have to rule-out Matrix.org because it's based in the UK, and it has been compromised by this push for ID-verification by force of law.

https://www.reddit.com/r/privacy/comments/1mdgbi4/matrix_homeserver_the_default_one_set_in_the_uk/

Any online service which is based in the UK, Australia and New Zealand would be subject to this same legislation. Perhaps instances located outside of the Commonwealth would work?