One feature I'd love to see is automatic grouping, combined with the functionality you offer already.

So for example if you have an email (using a custom domain): email@example.com

You obviously will receive emails as you give out your email. Say for example you get emails from the following senders:

- mail@google.com

- azure@microsoft.com

- notice@azure.com

- ok@imgur.com

- hello@startup.com

It would be nice if the dashboard had something like the following (almost like meta emails):

  Email Address                       Enable
  email-mailgooglecom@example.com     [x]
  email-azuremicrosoftcom@example.com [ ]
  email-noticeazurecom@example.com    [x]
  email-okimgurcom@example.com        [ ]
  email-hellostartupcom@example.com   [ ]

The reason for this is that rather than deal with the flaky "unsubscribe" you can just disable emails from that sender. With what you have now you could accomplish the same thing by creating aliases for each service, but the issue is that sometimes you receive emails from unexpected address (e.g. you give your email to Microsoft for billing but start receiving from their marketing department).

The above, combined with intelligent grouping of emails and a uBlock Origin like curated list of "bad" emails could truly eliminate all spam.

You should introduce a 4th tier of payment if you have the above functionality, by the way as it's not that trivial.

The end result of this would probably look something like:

Your email (custom domain): mail@example.com

  Group                                Enabled
  Microsoft                            [o]
   - Azure Emails                      [ ]
   - Microsoft Store                   [x]

  Google                               [x]
   - Google Cloud                      [x]

And you then would allow people to customize what emails constitute "Microsoft", "Azure Emails", etc.