A nice variation of this is plus addressing. The advantage it has over a catchall/wildcard is not attracting or being susceptible to random spam (i.e. when a spammer just sends emails to a ___domain using common names like david@ or mike@ etc.).

If you don't run your own mail server, Fastmail offer it (and have a nice fallback for the occasions where a badly coded site doesn't accept email addresses in the form of [email protected] ...I'm looking at you microsoft!): https://www.fastmail.com/help/receive/addressing.html