memordo - Spaced repetition tool to help you retain more knowledge
Stories - Master complex materials through short daily stories.
Harken - Flashcard app using smart repetition to improve your memory
Mochi - Write notes and flashcards with Markdown and study them with spaced repetition.
Zorbi - Spaced-Repetition Flashcards - Other tools are built by boomers, Zorbi is built by students.
Glean.co - Personalized learning for educational video lessons