Twitter, Wikipedia, Uber, Levi Strauss, Yelp, Airbnb
Major companies headquartered south of San Francisco:
You Tube, Visa, Facebook, Google, Quora, LinkedIn
From a longer list, I picked companies I have patronized. Find the complete list here:
en.wikipedia.org/wiki/List_of_companies_based_in_the_San_Francisco_Bay_Area