Anki - Anki is a program which makes remembering things easy. Because it's a lot more efficient than traditional study methods, you can either greatly decrease your time spent studying, or greatly increase the amount you learn.
Treehouse - Treehouse is an award-winning online platform that teaches people how to code.
LimeSurvey - LimeSurvey: the Online-Umfrage Tool - Open-Source Suryeys
Teachable - Create and sell beautiful online courses with the platform used by the best online entrepreneurs to sell $100m+ to over 4 million students worldwide.
Quizlet - Quizlet allows you to review and create flashcards for a variety of subjects, such as math and reading.
PowerSchool - PowerSchool provides a K-12 education technology platform for operations, classroom, student growth, and family engagement.