I've done alice@myname.com, bob@myname.com, etc. I don't keep track of them carefully so I may pick the same name for two different sites.

It also makes it easier to pass off a fake realname! Hi I'm John Smith, jsmith@oneofmydomains-nottooobvious.com...

You can even pick a domain sound like a legitimate mail service or company, e.g. jsmith@jgs-consulting.com.or jsmith@liberty-mail.io

All domains and addresses in this comment are fictitious - overlap with real domains is coincidental.