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.
GBWhatsapp - GBWhatsApp is a similar version for WhatsApp Plus have many new features
Telegram - Telegram is a messaging app with a focus on speed and security. It’s superfast, simple and free.
WaStat – WhatsApp tracker - WaStat – WhatsApp tracker app shows the last online time of a phone number at a glance, so you can contact them whenever they get online to share something important to them.
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.
Whatsdog Last Seen - Whatsdog Last Seen app shows the accurate last online time of all the phone numbers in your contact list to message them right on time and get an instant reply from them.