Google Classroom - Learning management tool by Google
newrow - Create your online school and deliver interactive content.
Edmodo - Where Learning Happens
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.
schoology - An online learning, classroom management & social networking platform that provides educators & students w/ more effective, efficient & engaging ways to learn.
Clever.com - syncing between education applications for K-12 schools