Please bookmark ToS;DR. This is one of your main search engines this year.

Specifically, you are looking for rules in the theme of "data brokerage"; rules such as:

• Amazon's "Voice data is collected and shared with third-parties",
• Facebook's "Deleted content is not really deleted",
• Apple's "Your personal data may be disclosed to comply with government requests without notice to you",
• Reddit's "Tracking via third-party cookies for other purposes without your consent.",
• YouTube's "This service can view your browser history",
• Quora's "They store data on you even if you did not interact with the service",
• PayPal's "This service still tracks you even if you opted out from tracking"

These are only chosen from the homepage! You're responsible for searching the apps you use. Ignorance may be a popular excuse, but when apps sell your data, these are the buyers.