Top Alternatives to Instantbird

Pidgin is a free and open-source chat client which supports AIM, Google Talk, ICQ, XMPP protocols.

Telegram is a free cloud-based instant messaging platform.

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

Trillian is a proprietary multiprotocol instant messaging application.

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

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

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

Psi is a free instant messaging application designed for the XMPP network (including Google Talk). Fast and lightweight, Psi is fully open-source and compatible with Windows, Linux, and Mac OS X.

Kopete is a multi-protocol, free software instant messaging client released as part of the KDE Software Compilation. Although it can run in numerous environments, it was designed for and integrates with the KDE Plasma Workspaces.

ICQ is an open source instant messaging software.

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

qutIM is free and open-source multiprotocol (ICQ, Jabber, Mail.Ru, IRC, VKontakte) instant messenger.

Coccinella is a free and open-source cross-platform client for the XMPP/Jabber-instant messaging-protocol.

Zulip is a chat and collaborative software.

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

Dasher Messenger provids a way to message friends.