DevDocs - Open source API documentation browser with instant fuzzy search, offline mode, keyboard shortcuts, and more
Padlet - Visual boards for organizing anything.
Zeal - Zeal is an API Documentation Browser.
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.
Loom - Loom is a screen recording extension for Chrome that gives people the ability to create and share media. Create your own videos using your camera, screen view, and audio. Read more about Loom.
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.