Fastmail ($50/year) unlimited domains aliased to 1 account looks like best in class based on comments in this thread-- https://news.ycombinator.com/item?id=22789401 .
Migadu (now $90/year) was formerly the go-to based on its old prices. Then they auto-renewed my annual subscription without notification at about 2x the price. Looking to move away in case they do that again.
Mailbox.org (1€/month/e-mail) looks promising.
Zoho mail ($1/month/e-mail) also looks promising.
Another option is FOSS self-hosted, which actually looks more safe in 2021. The major problem is finding an IP that's not blacklisted. Mailcow: https://mailcow.github.io/mailcow-dockerized-docs/ . Completely dockerized. 6gb ram required (VPS in the ~$40/month range)
Mailinabox: 1gb ram required (VPS ~$10/month). Same problem with having to deal with blacklisting, much less ram required though. Can also use dockerized version.
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Full disclosure: I run https://hanami.run , an email forwarding service which allow you to add 3 domains, unlimited alias(mailbox) catch all. And If you enable Log Mail(Disable by default), you can read email right in our website.