1. Coursera: Coursera is an online learning platform that offers courses from universities and organizations worldwide. It provides access to high-quality educational content and credentials to learners globally.

2. Udemy: Udemy is a marketplace for online learning, offering a wide range of courses taught by experts in various fields. It allows users to learn at their own pace and offers certificates upon completion.

3. Khan Academy: Khan Academy is a non-profit organization that offers free educational content in the form of video lessons, practice exercises, and quizzes. It covers a wide range of subjects, from math and science to humanities and test preparation.

4. Duolingo: Duolingo is a language-learning platform that provides free courses in multiple languages. It uses gamification techniques to make learning engaging and accessible to a wide audience.

5. edX: edX is a massive open online course (MOOC) provider created by Harvard and MIT. It offers courses from top universities and institutions worldwide, providing learners with the opportunity to earn certifications and degrees.

6. Quizlet: Quizlet is an online learning platform that offers flashcards, quizzes, and study games. It allows users to create their own study materials or choose from a vast library of pre-made content.

7. Byju’s: Byju’s is an Indian edtech company that offers personalized online learning programs for students from kindergarten to grade 12. It uses a combination of videos, interactive activities, and assessments to enhance learning outcomes.

8. Kahoot!: Kahoot! is a game-based learning platform that allows educators to create interactive quizzes, surveys, and discussions. It promotes student engagement and facilitates formative assessments.

9. ClassDojo: ClassDojo is a communication platform that connects teachers, parents, and students. It enables teachers to share updates, photos, and videos on student progress and allows parents to stay involved in their child’s education.

10. Codecademy: Codecademy is an online coding education platform that offers interactive coding lessons in various programming languages. It aims to make programming accessible to everyone, including beginners and experienced developers.

These startups and innovations have revolutionized the education sector by providing accessible, flexible, and engaging online learning platforms and tools.