For Stanford, you can start here: https://explorecourses.stanford.edu/.This https://explorecourses.stanford.edu/.This should give you enough information about t

For Stanford, you can start here: https://explorecourses.stanford.edu/.This https://explorecourses.stanford.edu/.This should give you enough information about the various classes and their professors/lecturers. From there you can try searching for the course numbers on google. Most will have a website that hosts most of the material you may be interested in.