Hunter - Find all the email addresses related to a domain

Reddit - Reddit gives you the best of the internet in one place. Get a constantly updating feed of breaking news, fun stories, pics, memes, and videos just for you.

Snov.io - More leads. More sales. More revenue.

Contextly - Contextly provides content recommendation system for publishers.

Apollo.io - Apollo’s predictive prospecting, sales engagement, and actionable analytics help the teams to reach its full revenue potential.

Digg - Digg delivers the most interesting and talked-about stories on the Web right now.