Udemy
A VAST variety of Online Courses.

I LOVE this site, it has so many different courses from childhood psychology to Tai Chi to programming. It's great! Unfortunately some of these courses are really expensive... BUT Udemy has many discounts so if you have your eyes set on a particular course, just wait for the next big sale. It offers online courses in:
Web, Software, Game Development and co
Business (e.g Human Resources, Law, Media, Finances...)
Personal Development (Happiness, Creativity, Self-Esteem...)
Design (Game, Web, 3D...)
Lifestyle (Pet Care, Beauty & Make-Up, Food... (I know) )
Photography
Heath & Fitness (Yoga, Nutrition, Meditation...)
Music
Test Prep (SAT, TOEFL etc)
Teacher Training
High school courses (Science, Engineering, Language, Psychology...)
And many more