The famous quote from Lord Acton—“Absolute power corrupts absolutely”—is a good guide to compiling a list of the companies that are likely to need policing. The list is pretty short—Amazon, Facebook, Google (including YouTube), Twitter, and Uber (perhaps). And the effect on humankind (especially children) is pretty severe. Amazon is now so large and powerful that it is in danger of being prosecuted under the antitrust laws.
And Facebook and Google make bags of money from advertisers, and have a continuing series of privacy violations.
Fortunately, a handful of Silicon Valley notables have become activist vigilantes. And they are aiming at kids to use their smartphones for healthy purposes rather than wasting time on useless social apps.