NSLs: https://www.eff.org/issues/national-security-letters/faq
Dragnet/Geofence warrants: https://www.nbcnews.com/news/us-news/google-tracked-his-bike... and https://www.logically.ai/articles/geofence-warrants-on-the-r...
Dragnet/Mass-surveillance keyword warrants: https://www.forbes.com/sites/thomasbrewster/2021/10/04/googl...
Dragnet/mass-scanning of online storage: https://www.forbes.com/sites/thomasbrewster/2021/12/20/googl...
PRISM: https://en.wikipedia.org/wiki/PRISM_(surveillance_program)
RAMPART-A: https://en.wikipedia.org/wiki/RAMPART-A
Forced backdoors into "encrypted" email: https://www.theregister.com/2020/12/08/tutanota_backdoor_cou...
And who knows what else is still secret. A good rule of thumb is that if something's in the "cloud" or hosted on someone's computer that you don't directly control, you should assume that LEOs have access to it.
When all the data is centralized, you don't care about the end-point encryption. All you care about is having access to all the databases.