I have studied all my life, so when I was struggling to get a job and had little money, was not eligible for any fee subsidy and I was close to retirement; I went looking for something to stimulate my intellect. I gave up on outlaying money on a career changing course because there was little hope of work. Then I discovered Future Learn https://www.futurelearn.com/
These are free courses, designed as professional development and / or self-help etc. The courses are offered by Universities over the world, and increasingly by other entities. Some give you credit towards other degrees, some are teasers for degrees or post grad work, some are serious professional development for professionals, but anyone can sign up. A year ago the free, and unlimited access was changed to free, but not allowed to take the assessment with access ceasing after a set period; and, for a small fee, assessment and statement of attainment and unlimited access. I have mostly done free, but now I have a little extra money I have paid the fee to support those courses I found most useful.
Other “free” courses I have done include one from Lynda which my Council’s library hosted, but you could only do it on old library computers and that was $2/half hour and opened late, closed for lunch and closed early, so lots of broken sessions.
So I don’t have a lot to compare Future Learn with, but the courses I enjoyed the most were Food as Medicine (Monash Uni), The Molecular Mechanisms of Ageing, Jazz Piano, Solar Photovoltaics, Geology, Citizen Science; Soils, Genealogy, Maths Puzzles, WWI in 100 stories, Quakers, Autism, Liver Disease. Some were not greatly inspiring eg Know your Abdomen.
My Uni background is mostly by distance ed, Accounting, IT, Education, Arts, Local Govt/Business, Civil Engineering, Health. I have also done short courses with TAFE.