Some of the more popular sinkhole lists include (in no particular order):
- www.MalwareDomains.com
- www.Malware.com.br
- www.MalwareDomainList.com
- www.MalwareURL.com
- www.SomeoneWhoCares.org
- mtc.sri.com
- www.MVPs.org
- www.UrlBlacklist.com (not free)
ref: https://www.sans.org/blog/windows-dns-server-sinkhole-domains-tool/