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.

Boomerang Respondable - Write perfect emails with Artificial Intelligence

Padlet - Visual boards for organizing anything.

Mailbutler - Mailbutler adds lacking functionality to email clients and increases your productivity

Socrative - Socrative helps teachers engage the class with educational activities to measure and visualize...

Boomerang for Gmail - Boomerang for Gmail is a Firefox / Chrome plugin that lets you take control of when you send and receive email messages.