Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
Messenger for Mac - Facebook Messenger wrapped up as a desktop app
Facebook Messenger - Facebook Messenger is a faster way to message.
Chat for Mac - Facebook Messenger & Chat on your Mac
Amity - Amity's Customer Relationship Hub simplifies customer success management.
Chatty - Chat with strangers all around the world in Messenger