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.

ChargeOver - ChargeOver automates recurring billing, subscription billing, & payment acceptance. A SaaS that integrates with Xero, Quickbooks, & has an API. Free trial.

Clever - syncing between education applications for K-12 schools

fusebill - Fusebill is the leading recurring billing and subscription management software for businesses. Try Fusebill for subscription billing made easy!

Claroline - Claroline is a collaborative eLearning and eWorking platform.

Elorus - A super-easy online invoicing & time tracking software