https://www.reddit.com/r/OSINT/comments/yy0vv0/how_do_i_do_a_reverse_phone_lookup_for_free/
19 votes, 33 comments. So I have a phone number someone wanted me to lookup for an investigation I'm doing to help someone out.

https://www.411.com/reverse-phone-lookup
411 reverse phone lookup service is free. Enter a phone number, search and find the phone owner's full name, address and more. Find out who called you.

https://thatsthem.com/reverse-phone-lookup
Next time you receive a phone call with no caller id, use ThatsThem's reverse phone number search to identify the caller in real-time. You can even get results ...