Trillian is a proprietary multiprotocol instant messaging application.

Franz is a free messaging app /former emperor of Austria, that combines chat & messaging services into one application.

Smuxi is a cross-platform IRC client for the GNOME desktop inspired by Irssi.

Empathy is an instant messaging (IM) and voice over IP (VoIP) client which supports text, voice, video, file transfers, and inter-application communication ov…

Instantbird is a cross-platform instant messaging client based on Mozillas XULRunner and the open source library libpurple used in Pidgin.