Audible.com - Books abound with excellent information, but making the time to read can be challenging. I use Audible.com when commuting or during other periods of the day that may lend themselves to being unproductive. See trieditreviews.com
Udemy.com - Udemy.com is full of great learning content. The best time to buy courses from Udemy.com is when courses are on sale; generally at very discounted prices. I use Udemy.com when I need a self-paced course. The content you buy on Udemy.com is accessible whenever you want it.
Coursera.org - Coursera.org offers excellent learning opportunities from established universities; from party schools to the Ivy League. Coursera.org has some unique course offerings and great content. If you need deadlines and a dictated pace, Coursera.org is a very useful resource. Coursera.org is free, but if you want a certificate of accomplishment, it does have a fee.
Lynda.com - Lynda.com is a subscription site. I use Lynda.com when I have a dedicated week or weekend to consume the course. The monthly subscription can be activated or deactivated on a monthly basis. Once your subscription is over, you do lose access to the website content
edX.org - edX was founded by Harvard University and MIT in 2012. Not unlike Coursera.org edX is an online learning destination and MOOC provider offering high-quality courses from the world's best universities and institutions.
codecademy.com - Codecademy offers free interactive coding courses online. Codecademy does offer premium content to enrich and support the learning experience. Currently, my favorite online learning platform for coding.
KhanAcademy.org - Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. Khan Academy offers curriculum for all ages in math, science, computer programming, history, art history, economics, and more.
DataCamp.com - DataCamp is an online resource that teaches R, Python and data visualization for data science.
Udacity.com - Udacity is an online resource that offers Nanodegrees. Udacity has partnered with today's leading companies to identify skills and develop curriculum to cultivate those skills. Complete one of Udacity's Nanodegree Plus certifications and get a guaranteed job or your money back!