NKill, the Internet Kill Board.

Back in 2001 the original NKill project was created to map out the network of trust between IP addresses, hosts, domains, and services; initially limited to Singapore, Indonesia, The Phillipines, Malaysia and Brunei. In 2006, the project was extended to include the .com, .net, .org, .biz and most of the ccTLD zones (well over 90 million domains and their associated hosts.)

The NKill search engine allows one to find potential hidden projects and websites for a given target, that may not be found with discovery tools like Maltego.It also provides you with the ability to discover interesting relationships between seemingly unrelated hosts and companies and pull vulnerable hosts for a specific domain, company or even a whole country.