Learning Resources for Ages 17+

Futurelearn
https://www.futurelearn.com
Free to access 100s of courses, only pay to upgrade if you need a certificate in your name

Seneca
https://www.senecalearning.com
For those revising at GCSE or A level. Tons of free revision content. Paid access to higher level material

Openlearn
https://www.open.edu/openlearn/
Free taster courses aimed at those considering Open University but everyone can access it.