Adding to this there is pidgin-otr and python-potr.

For IRC there is irssi-otr. There was weechat-otr but I think it may have gone unsupported as their script did not work in python3.

There is also ejabberd [0] that has OMEMO [1] preferred over OTR and PGP and supports many to many E2EE.

Someone tried to MitM Jabber, discussion here on HN [2].

[0] - https://ejabberd.im/

[1] - https://en.wikipedia.org/wiki/OMEMO

[2] - https://news.ycombinator.com/item?id=37955264