Although primarily with OpenLearn, since about 2007 - I've (thanks to the MAODE modules) found out about and used open resources from:
Although I signed up to OldMOOCs this never really got off the ground for me due to other commitments, always a bit of a concern as regards MOOCs e.g. engaging with it in the first place and then continuing to do so. I've however overcome this with FutureLearn due to selecting especially thrilling topics.
I've also found lots of open resources through Pinterest.
Just remembered I love accessing TED talks on my phone - great for when cooking, washing up or commuting. Background learning to take your mind off the hum-drum