Use a reputable service like Have I Been Pwned to see if your email address has appeared in any known data breaches.
If you are concerned about your own data being in a list like this: 3.4 Million HQ Combolist.txt
If you find a site hosting these files, you can report it to: Use a reputable service like Have I Been
Generate unique, complex passwords for every account so that one leak doesn't compromise your entire digital life. or banking portals
Hackers use automated tools to test these millions of logins across popular sites like Netflix, Amazon, or banking portals, banking on the fact that people reuse passwords.
183 Million Credentials Misreported as a Gmail Breach - Enzoic