Have i been pwned >> https://haveibeenpwned.com/

pwned websites >> https://haveibeenpwned.com/PwnedWebsites

How Do Spammers Get Your Email Address?
https://www.howtogeek.com/180477/htg-explains-how-do-spammers-get-your-email-address/

Guessing Email Addresses
http://www.bustspammers.com/guess-email-address.html

[b]What About Wrong Guesses?[/b]

What about them? Nothing! It’s not like it costs anything to send another email. Or another 10,000 emails. So what, if most of them go to non-existing addresses? And since the From address is always faked, the bounces will not flood the spammers own computer, but some innocent victim whose email address had been used in the From field.