There are lots of feeds related to fraudulent and malicious domains and IPs, but we're seeing more and more social engineering attempts coming in via phone.
When these are reported to us, I'd like to document the phone number in our intelligence repository and cross-reference the number with our VoIP records to see who else in the organization they may have contacted.
The only problem is, we get very few reports and we don't know what numbers we don't know about. Manual searches yield a lot of other low-fidelity data on generic phone-scraping sites.
At the risk of seeking product recommendations, does any organization publish anything like the Emerging Threats IP blocklist but for phone numbers?