Green Messenger - WhatsApp Messenger Web for Chrome. Text/Chat on computer. Notifications, messages, tools.
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.
WhatsApp Web To Go - WhatsApp Web client for your phone/tablet with media support
Zulip - Chat for distributed teams. Zulip combines the immediacy of real-time chat with an email threading model. With Zulip, you can catch up on important conversations while ignoring irrelevant ones.
App for WhatsApp by coldX - Integrated WhatsApp functionality on the Desktop.
WowApp - Wowapp is the best alternative to Skype and you will get paid to use it!