[ConcernedCitizen]

The one that you have root access too. Seriously, if you can't verify it, the encryption standards or security overall is anybody's guess. It's better to control the domain. It's also better to practice end-to-end (asymmetric encryption preferred) as the end-user, to prevent unauthorized access to your secrets. But, THAT said, if you can't do any of that yourself or you simply prefer the convenience you can trust your data to a well-researched, peer-reviewed service. You should always encrypt by default instead of relying on a single point of failure. I feel like I've said "single point of failure" a lot lately.

That's exactly what I always think! Why not have your own domain on your own server? Then you have everything under control yourself.
But thank you for the huge list. Will check some of the providers myself as I just know about protonmail...

I'm always here to help, feel free to PM me. And really, if you don't have your own website and server by now, you should go get them right now. It takes 5 minutes. You can have free SSL certificates with Let's Encrypt, a free domain with the purchase of a dot com, and other very cheap TLD's. You can even get free backups with most setups AND some even include SSH by default (they should anyways) to every individual server. Which, speaking of that, you should really try out virtual servers in general, because the possibilities are endless when it comes to virtualization, especially when you are talking about rapid deployment and storage. I have a home NAS that cost me $300 and I can connect to securely using a home VPN. All it costs now is whatever my internet costs, so I have saved thousands by using that instead of Netflix, Hulu, etc.