- https://www.passivetotal.org
- https://www.robtex.com
- https://dnstrails.com
- https://whois.domaintools.com
- https://domainbigdata.com
- https://www.domaincrawler.com/
- https://whoisology.com
- https://www.dailychanges.com/
- https://www.dnsinspect.com/
- https://centralops.net/co/domaindossier.aspx
- https://www.bfk.de/bfk_dnslogger.html
- https://passivedns.mnemonic.no/search/
- https://www.statsinfinity.com/
- https://www.domaingraveyard.com/
- https://www.whoismind.com/
- https://who.is/
- https://www.whatsmydns.net
- https://www.whoisxy.com/
- https://domainpunch.com
- https://domainpunch.com/tlds/search.php
- https://viewdns.info
- https://www.activednsproject.org/
- https://www.statdns.com/
- https://reverse.report/
- https://blog.opendns.com/security-graph
- https://urlquery.net/
- https://www.virustotal.com/search
- https://registry.opendata.aws/rapid7-fdns-any/
- https://securitytrails.com/dns-trails
- https://www.expireddomains.net/
- expired or deleted domains