There are many great suggestions---some that I might argue are better than what I have to add (Lewin, Sapolsky, Sedgewick, Boyd)---but I have some to add that I enjoyed because they were extremely well-taught:
I absolutely with anything by Patrick Winston! I put on his lectures whenever I need to feel inspired about my job. He's so engaging and has a great way of explaining things that leave students feeling motivated and curious. Additionally, his book "Make it Clear" has been a Godsend to my academic and my personal writing.
* Donald Sadoway's Solid-State Chemistry lectures: https://www.youtube.com/playlist?list=PL36EC6A6180271B0F
* Anything by Patrick Winston, e.g. "AI": https://www.youtube.com/playlist?list=PLUl4u3cNGP63gFHB6xb-k...
* robert ghrist's calculus lectures, which were somehow clearer/more engaging than others I had found: https://www.youtube.com/playlist?list=PLKc2XOQp0dMwj9zAXD5Ll...