Trillian
Freemium
Trillian is a proprietary multiprotocol instant messaging application.
IM+
Freemium
IM+ supports simultaneously major IM services, including Google Talk, Twitter DMs, Yahoo!, AIM/iChat, ICQ, Jabber (and Slack through Jabber), etc.
Facebook Messenger
Free
Facebook Messenger is the official Facebook app that lets you have text conversations with all of your friends on the popular social network.
ICQ
Free
ICQ is an open source instant messaging software.
Compare Adium with alternatives
Compare Facebook Messenger and Adium and decide which is most suitable for you.