Linkello - Video calls simplified, no installation required.
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.
jTorchat - jTorchat stands for Java Torchat, and is a complete rewrite of the popular p2p IM messenger Torchat
Green Messenger - WhatsApp Messenger Web for Chrome. Text/Chat on computer. Notifications, messages, tools.
Signal - Fast, simple & secure messaging. Privacy that fits in your pocket.
App for WhatsApp by coldX - Integrated WhatsApp functionality on the Desktop.