SJ – jabber-client for secure communication protocol XMPP. Supports encryption of messages using the OpenPGP in the automatic mode, stores the history of cryptography, it is compatible with all the jabber-clients and GoogleTalk.
Konversation is a user friendly Internet Relay Chat client.
Advanced IRC for Mac OS X
IRC instant messaging gateway
Lite and text only IM/Chat Client for Second Life
EZ Intranet Messenger is a messenger client for internal communication.
Licq is a multi-threaded multi-protocol chat client written mostly in C++.