Does anyone use OpenLearn?Watch
OpenLearn specifically has a huge range of material, much of which is taken from discontinued (and some current) Open University courses. These range from basic introductory courses on things like arithmetic or using calculators to 100 hour extracts from masters degree level modules. I'd say give it a shot, and also try FutureLearn, which is also an Open University initiative which features courses from themselves, other universities and even organisations like the European Space Agency (their course on climate monitoring from space was a really good one).
Definitely give it a try, but don't expect to earn real qualifications.
Compared to Futurelearn, OpenLearn is miles ahead. FL's materials and methods are quite weak, IMO. They certainly don't stand up to their competitors, EdX and Coursera.