Crunchbase - Crunchbase is a platform for discovering industry trends, investments, and news about companies around the world.
FullContact Card Reader - Automagically scan biz cards into LinkedIn/Gmail contacts
AngelList - Access top deals through investor-led syndicates
Clearbit Connect - Clearbit Connect is a free extension that surfaces actionable information on the people who email you.
Private Equity List - Private equity, venture capital database that focuses on growing sectors in emerging countries and contains contacts of investment professionals.
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.