I only mention the paid providers I have tried, if I include the free ones the list would be too long
1. Office 365 - business - it's really business targeted. After a month I switched to home edition and this is what I needed.
2. Fastmail - nice webmail, a lot of features, however I stopped using it after the new Australian internet law was adopted.
3. Runbox - solid provider but webmail is the worst. Just think of it as a provider with no webmail. It has an unsupported roundcube installation but you still need to login to their default webmail to setup and admin your account. The new webmail they are working at is even worse. They just don't get the webmail part of email.
4. Tutanota - solid provider, simple webmail with a lot of features I need missing. You can't use IMAP.
5. Mailbox.org - nice OX webmail but email delivery is slow. Looking at some logs I can see that their incoming mail servers timeout very often. Incoming mail is delayed very often for more hours at a time.
6. Protonmail - a little bit expensive when I set up all the features I want to use. It's encrypted but you can use IMAP with a bridge app they provide for paying accounts. Sometimes it works, sometimes it freeze.
7. Namecheap email - OX webmail, cheap, but it doesn't allow sending from the aliases you set up.