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

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

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

AdiInviter Pro is a contact importer and tell-a-friend platform.

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

Yahoo! Messenger (sometimes abbreviated Y!M) is an advertisement-supported instant messaging client and associated protocol provided by Yahoo.

MailStore lets you archive your private email from almost any email source and search through them extremely quickly.