Top Alternatives to Tkabber

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

Hangouts is an instant messaging software developed by Google.

WhatsApp Messenger is an instant messaging platform owned by Facebook.

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

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.

Wire is a cross-platform, encrypted instant messaging client created by Wire Swiss. It is available for iOS, Android, Linux, Windows, macOS and Web browser clients.

appear.in provides one-click video conferences right in your browser without requiring PIN codes or additional software.

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

Apache Spark is an open-source cluster-computing framework.

Tango is the messaging app with the best video calling. All messages and calls are free.

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

Zulip is a chat and collaborative software.

Phoner and PhonerLite are softphone applications for Windows operating systems available as freeware.

Dasher Messenger provids a way to message friends.