Txti - Fast web pages for everybody
Padlet - Visual boards for organizing anything.
share.link - A fast and easy way to organize and share your links
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.
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.
Brace - Access to the best developers for $0