Adium is an Open source multi-protocol instant messaging client for Mac OS X, supports MSN, Jabber, Yahoo! and other networks.

Disa is your new messaging hub. Conversations from different services can seamlessly be joined together, or disbanded within seconds.

Facebook Messenger is the official Facebook app that lets you have text conversations with all of your friends on the popular social network.

ICQ is an open source instant messaging software.

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

Linphone is a free voice over IP (VoIP) service and SIP client.

Conversations is an open source XMPP/Jabber client for the Android platform.

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

Gajim is an instant messaging client for the XMPP protocol which uses the GTK+ toolkit.

IM+ supports simultaneously major IM services, including Google Talk, Twitter DMs, Yahoo!, AIM/iChat, ICQ, Jabber (and Slack through Jabber), etc.

KakaoTalk (Korean: 카카오톡), or sometimes KaTalk, is a free mobile instant messaging application for smartphones with free text and free call features.

Miranda IM is an open source multiprotocol instant messaging application, designed for Microsoft Windows.