Learney - Knowledge aggregator for developers
NWEA Assessments - NWEA Assessments creates a personalized assessment experience by adapting to each student's learning level.
Multiplication Kingdom - Learn the times tables by playing and having fun in the Multiplication Kingdom (for kids and adults!)
ALEKS - ALEKS is a web-based artificially intelligent assessment and learning system that uses adaptive questioning to accurately determine exactly student knows.
Khan Academy - Khan Academy offers online tools to help students learn about a variety of important school subjects. Tools include videos, practice exercises, and materials for instructors. Read more about Khan Academy.
iSpring QuizMaker - iSpring Quiz Maker is easy-to-use quiz software. Create interactive quizzes and surveys in HTML5 & Flash and embed them in a website or publish for any LMS!