Proofy - Quickly validate and verify your email lists.
Unlimited Criminal Checks - Unlimited Criminal Checks is a criminal records database that provides you with instant access to unlimited criminal check reports.
Trumail - Free email verification API
Infotracer - Infotracer is an online public record provider software program that enables you to find any information about the person of interest.
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
FastPeopleSearch - Research people reverse lookup various pieces of information similar.