I love his videos, but not because they efficiently present tutorial content. He's an amazing teacher because he demonstrates an attitude/approach to learning that would be difficult to convey through text.

Wow, this guy makes me a bit sad, because I did a 4 year Elec Eng degree and the guy that taught semi conductors was so bad. Almost everyone failed the exam because they had no idea what he was talking about (lots of the other modules were good). I (re)learnt more from watching a few of these videos than I did in a semester at university.

I looked at my department website, it's 25+ years since I started uni and the 2 lecturers I had the most trouble learning from are still there. One is had of department! He was a good guy, I just didn't "get it", but the other one was awful at teaching. He did have amazing credentials from Stanford and another top tier uni in the States before coming over to the UK. Teaching was never a priority at that uni!

Are there any websites/services that curate the best videos on specific school topics? With broader coverage than Khan Academy?

Searching on YouTube find thousands of matches, and I am exhausted after 20 minutes of previewing search results.