Zeal - Zeal is an API Documentation Browser.
Padlet - Visual boards for organizing anything.
DevDocs - Open source API documentation browser with instant fuzzy search, offline mode, keyboard shortcuts, and more
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.
Snippely - Snippely is a basic text and code organizational tool.
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.