Snarl - Snarl is a notification system for Windows.
Conversations.im - XMPP client designed with ease of use and security in mind
Zoom - Equip your team with tools designed to collaborate, connect, and engage with teammates and customers, no matter where you’re located, all in one platform.
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
Hubgets - Chat, voice, and video turning team communication experience into knowledge to help your business get more productive
Xabber - Open source Jabber (XMPP) client with multi-account support, clean and simple interface.