HBX Core
Its a paid online business course by Harvard Business School with 3 modules - Business Analytics, Economics for Managers, Financial Accounting
Material is not super challenging (maybe except for Accounting), but its still a lot of work and very rewarding. There is a strong social element to the course because they incentivize students to ask and answer each other's questions. At the end of it, you have to go to a testing centre and give a 3 hour exam on everything they have taught you. I finished this course a few months ago and really enjoyed the material and all the people I met through it. Highly recommend!