HEY - Email at its best, new from Basecamp.
Clearbit - Clearbit provides Business Intelligence APIs
InstAddr - Disposable email address application.
ZoomInfo - ZoomInfo is a B2B database providing detailed business information on people and companies.
Horde - Horde Groupware is a free, enterprise ready, browser based collaboration suite.
InsideView - InsideView aggregates and curates all the company and contact data, news and social insights, and professional connections you need to do business better.