Dear aspirant, Following are some useful courses you can do before you start your career in Engineering

• Swayam - https://swayam.gov.in/

• NPTEL - https://onlinecourses.nptel.ac.in/

• Mooc - http://mooc.org/

• Edx - https://www.edx.org/

• Coursera- https://www.coursera.org/

• Udacity - https://in.udacity.com/

• Udemy - https://www.udemy.com/

• Khanacademy - https://www.khanacademy.org/

• Skillsahre - https://www.skillshare.com/

• Harvard University - https://online-learning.harvard.edu/

• Ted - https://ed.ted.com/

• Alison - https://alison.com/

• Futurelearn - https://www.futurelearn.com/

• Web Development - https://digitaldefynd.com/best-free-web-development-courses-tutorials-certification/

• Digital Marketing - https://digitaldefynd.com/best-free-digital-marketing-certifications/

• IOS app development - https://digitaldefynd.com/best-ios-app-development-course-tutorial/

• Open Learn - http://www.open.edu/openlearn/

• Tuts Plus - https://tutsplus.com/

• Open Culture - http://www.openculture.com