Improver - Improver Chrome extension helps you to find personal email addresses from social networks.
SignalHire - Valid personal & work emails and phone numbers. Real-time verified contact info for recruiters, sales professionals, and marketeers.
Hunter - Find all the email addresses related to a domain
Ampliz Sales Buddy - Data to power your business
Lusha - Search less. Sell more.
SalesBlink.io - From Prospecting to Outreach to Closing at lightning fast speed.