This is a tracking ticket for multiple features relating to Muting, Blacklisting, or Blocking individual users.
In some cases, a user might want to use a single overall mute/block covering T138166: Allow users to restrict who can send them direct emails via Special:EmailUser, T150419: Allow users to restrict who can send them notifications and [T165124].
There may be uses cases for doing just one, particularly to block private email while still seeing other notifications. So I don't think we should take that away.
Reduce harassment by allowing individual users to control who can contact them across our network of Wikimedia wikis.
We will learn from the Echo Notifications blacklist how this is received and how a blacklist could be extended in the future.