Demandbase - Bizo
Zendesk - Zendesk is a beautiful, lightweight help-desk solution.
6sense - 6sense is a B2B predictive intelligence engine for marketing and sales.
Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community
Hushly - Hushly is a lead generating platform for buyers and vendors.
HelpScout - Help Scout is a simple, straightforward way to provide excellent support