mailbox.org
hey
fastmail
tutanota
mailfence
disroot
posteo
barracuda (for businesses)
vivaldi mail
mailpile
countermail
hushmail
I haven't used any of these, so if anyone has others or has experience with any of these, please share your experience.
And yeah, this UID situation with Protonmail is not good. As a long-time Protonmail customer, I've been concerned that they seem to have gotten bored with keeping a stable product.
Back to the point... I still will be using Protonmail because no product is perfect. For example, Fastmail I believe is in Australia which is one of the last western nations where I would want my data to be stored. I wouldn't use them, but does that mean someone else shouldn't use them? Not really. All of these products have tradeoffs. Since Protonmail's delete function is likely to still work most of the time, I won't yet be abandoning them. Fact is that I find all of the alternatives preferable to relying upon The Google.
But, it just works once its setup, and if all you want is IMAP support it's all good there. They usually do a Black Friday sale that's pretty decent. Last year they had a 25gb storage option for $25/year. I have like 5 domains on it, and about as many mailboxes. Smooth sailing since.
If anyone here is looking for a business idea, I would absolutely sign up for an email service that is based in U.S. and provides a guarantee (in writing) that it 1) doesn't track the user across the web after they sign in to email 2) doesn't scan or parse data from emails in any way 3) doesn't sell any information it obtains from me or about me to any third party 4) doesn't make any of its money at all from advertising 5) maintains high operational security standards.
Notice that I'm not even asking for end-to-end encryption like Protonmail provides. I just want something that is in my home country's legal jurisdiction (for business reasons), doesn't track me invasively nor sell my data, and is well-run.
I believe a company could make a lot of money if they communicated this offering to the public and maintained a decent brand reputation.