TelephoneLists.Biz - Telephonelists.biz is the source for phone leads for sale, provides the agents with a wide audience full of leads ready to become the next customers.
Clearbit - Clearbit provides Business Intelligence APIs
LeadGibbon - Access millions of business contacts, with verified email addresses and phone numbers
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.
Salestools - Monitor your Linkedin newsfeed for keywords to obtain leads.
InsideView - InsideView aggregates and curates all the company and contact data, news and social insights, and professional connections you need to do business better.