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.
BookWidgets - BookWidgets is an excellent application that let you create engaging exercises in minutes and easily share a varied variety of beautiful and fun activities with your classroom and others.
WhatsGreen Multi Messenger - Easy access to WhatsApp, Line, Telegram, FB Messenger and many others via the Chrome toolbar.
Padlet - Visual boards for organizing anything.
Green Messenger - WhatsApp Messenger Web for Chrome. Text/Chat on computer. Notifications, messages, tools.
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.