B4R - Development tool for native Arduino programs.
Padlet - Visual boards for organizing anything.
Circuito.io - Instant code and wiring for your project
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.
embedXcode - embedXcode is a template for Xcode.
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.